LibJS: Stop propagating small OOM errors from Intl.NumberFormat

Note this also does the same for Intl.PluralRules. The only OOM errors propagated from Intl.PluralRules were from Intl.NumberFormat.
Author: https://github.com/trflynn89 Commit: b3694653a7 Pull-request: https://github.com/SerenityOS/serenity/pull/20854
2025-06-09 17:44:56 +09:00 · 2023-08-30 12:30:39 -04:00 · 2023-08-30 12:30:39 -04:00 · b3694653a7 · 2024-07-16 22:26:05 +09:00
commit b3694653a7
parent 30a812b77b
16 changed files with 153 additions and 164 deletions
--- a/Userland/Libraries/LibJS/Runtime/BigIntPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/BigIntPrototype.cpp
@ -91,7 +91,7 @@ JS_DEFINE_NATIVE_FUNCTION(BigIntPrototype::to_locale_string)
    auto* number_format = static_cast<Intl::NumberFormat*>(TRY(construct(vm, realm.intrinsics().intl_number_format_constructor(), locales, options)).ptr());

    // 3. Return ? FormatNumeric(numberFormat, x).
-    auto formatted = TRY(Intl::format_numeric(vm, *number_format, Value(bigint)));
+    auto formatted = Intl::format_numeric(vm, *number_format, Value(bigint));
    return PrimitiveString::create(vm, move(formatted));
 }

--- a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp
@ -538,7 +538,7 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
            value = floor(value * pow(10, static_cast<int>(*fractional_second_digits) - 3));

            // iii. Let fv be FormatNumeric(nf3, v).
-            auto formatted_value = MUST(format_numeric(vm, *number_format3, Value(value)));
+            auto formatted_value = format_numeric(vm, *number_format3, Value(value));

            // iv. Append a new Record { [[Type]]: "fractionalSecond", [[Value]]: fv } as the last element of result.
            result.append({ "fractionalSecond"sv, move(formatted_value) });
@ -622,13 +622,13 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
            // viii. If f is "numeric", then
            case ::Locale::CalendarPatternStyle::Numeric:
                // 1. Let fv be FormatNumeric(nf, v).
-                formatted_value = MUST(format_numeric(vm, *number_format, Value(value)));
+                formatted_value = format_numeric(vm, *number_format, Value(value));
                break;

            // ix. Else if f is "2-digit", then
            case ::Locale::CalendarPatternStyle::TwoDigit:
                // 1. Let fv be FormatNumeric(nf2, v).
-                formatted_value = MUST(format_numeric(vm, *number_format2, Value(value)));
+                formatted_value = format_numeric(vm, *number_format2, Value(value));

                // 2. If the "length" property of fv is greater than 2, let fv be the substring of fv containing the last two characters.
                // NOTE: The first length check here isn't enough, but lets us avoid UTF-16 transcoding when the formatted value is ASCII.
--- a/Userland/Libraries/LibJS/Runtime/Intl/DurationFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DurationFormat.cpp
@ -446,7 +446,7 @@ Vector<PatternPartition> partition_duration_format_pattern(VM& vm, DurationForma
                // 3. Let dataLocaleData be %DurationFormat%.[[LocaleData]].[[<dataLocale>]].

                // 4. Let num be ! FormatNumeric(nf, 𝔽(value)).
-                auto number = MUST(format_numeric(vm, *number_format, MathematicalValue(value)));
+                auto number = format_numeric(vm, *number_format, MathematicalValue(value));

                // 5. Append the new Record { [[Type]]: unit, [[Value]]: num} to the end of result.
                result.append({ unit, move(number) });
@ -505,7 +505,7 @@ Vector<PatternPartition> partition_duration_format_pattern(VM& vm, DurationForma
                auto* number_format = static_cast<NumberFormat*>(MUST(construct(vm, realm.intrinsics().intl_number_format_constructor(), PrimitiveString::create(vm, duration_format.locale()), number_format_options)).ptr());

                // 5. Let parts be ! PartitionNumberPattern(nf, 𝔽(value)).
-                auto parts = MUST(partition_number_pattern(vm, *number_format, MathematicalValue(value)));
+                auto parts = partition_number_pattern(vm, *number_format, MathematicalValue(value));

                // 6. Let concat be an empty String.
                StringBuilder concat;
--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp
@ -5,6 +5,7 @@
 */

 #include <AK/Checked.h>
+#include <AK/StringBuilder.h>
 #include <AK/Utf8View.h>
 #include <LibCrypto/BigInt/SignedBigInteger.h>
 #include <LibJS/Runtime/AbstractOperations.h>
@ -14,7 +15,6 @@
 #include <LibJS/Runtime/Intl/NumberFormat.h>
 #include <LibJS/Runtime/Intl/NumberFormatFunction.h>
 #include <LibJS/Runtime/Intl/PluralRules.h>
-#include <LibJS/Runtime/ThrowableStringBuilder.h>
 #include <LibUnicode/CurrencyCode.h>
 #include <math.h>
 #include <stdlib.h>
@ -257,7 +257,7 @@ void NumberFormatBase::set_trailing_zero_display(StringView trailing_zero_displa
        VERIFY_NOT_REACHED();
 }

-ThrowCompletionOr<Value> NumberFormat::use_grouping_to_value(VM& vm) const
+Value NumberFormat::use_grouping_to_value(VM& vm) const
 {
    switch (m_use_grouping) {
    case UseGrouping::Always:
@ -391,7 +391,7 @@ int currency_digits(StringView currency)
 }

 // 15.5.3 FormatNumericToString ( intlObject, x ), https://tc39.es/ecma402/#sec-formatnumberstring
-ThrowCompletionOr<FormatResult> format_numeric_to_string(VM& vm, NumberFormatBase const& intl_object, MathematicalValue number)
+FormatResult format_numeric_to_string(NumberFormatBase const& intl_object, MathematicalValue number)
 {
    bool is_negative = false;

@ -427,23 +427,23 @@ ThrowCompletionOr<FormatResult> format_numeric_to_string(VM& vm, NumberFormatBas
    // 4. If intlObject.[[RoundingType]] is significantDigits, then
    case NumberFormatBase::RoundingType::SignificantDigits:
        // a. Let result be ToRawPrecision(x, intlObject.[[MinimumSignificantDigits]], intlObject.[[MaximumSignificantDigits]], unsignedRoundingMode).
-        result = MUST_OR_THROW_OOM(to_raw_precision(vm, number, intl_object.min_significant_digits(), intl_object.max_significant_digits(), unsigned_rounding_mode));
+        result = to_raw_precision(number, intl_object.min_significant_digits(), intl_object.max_significant_digits(), unsigned_rounding_mode);
        break;

    // 5. Else if intlObject.[[RoundingType]] is fractionDigits, then
    case NumberFormatBase::RoundingType::FractionDigits:
        // a. Let result be ToRawFixed(x, intlObject.[[MinimumFractionDigits]], intlObject.[[MaximumFractionDigits]], intlObject.[[RoundingIncrement]], unsignedRoundingMode).
-        result = MUST_OR_THROW_OOM(to_raw_fixed(vm, number, intl_object.min_fraction_digits(), intl_object.max_fraction_digits(), intl_object.rounding_increment(), unsigned_rounding_mode));
+        result = to_raw_fixed(number, intl_object.min_fraction_digits(), intl_object.max_fraction_digits(), intl_object.rounding_increment(), unsigned_rounding_mode);
        break;

    // 6. Else,
    case NumberFormatBase::RoundingType::MorePrecision:
    case NumberFormatBase::RoundingType::LessPrecision: {
        // a. Let sResult be ToRawPrecision(x, intlObject.[[MinimumSignificantDigits]], intlObject.[[MaximumSignificantDigits]], unsignedRoundingMode).
-        auto significant_result = MUST_OR_THROW_OOM(to_raw_precision(vm, number, intl_object.min_significant_digits(), intl_object.max_significant_digits(), unsigned_rounding_mode));
+        auto significant_result = to_raw_precision(number, intl_object.min_significant_digits(), intl_object.max_significant_digits(), unsigned_rounding_mode);

        // b. Let fResult be ToRawFixed(x, intlObject.[[MinimumFractionDigits]], intlObject.[[MaximumFractionDigits]], intlObject.[[RoundingIncrement]], unsignedRoundingMode).
-        auto fraction_result = MUST_OR_THROW_OOM(to_raw_fixed(vm, number, intl_object.min_fraction_digits(), intl_object.max_fraction_digits(), intl_object.rounding_increment(), unsigned_rounding_mode));
+        auto fraction_result = to_raw_fixed(number, intl_object.min_fraction_digits(), intl_object.max_fraction_digits(), intl_object.rounding_increment(), unsigned_rounding_mode);

        // c. If intlObj.[[RoundingType]] is morePrecision, then
        if (intl_object.rounding_type() == NumberFormatBase::RoundingType::MorePrecision) {
@ -495,7 +495,7 @@ ThrowCompletionOr<FormatResult> format_numeric_to_string(VM& vm, NumberFormatBas

        // b. If i ≠ -1, set string to the substring of string from 0 to i.
        if (index.has_value())
-            string = TRY_OR_THROW_OOM(vm, string.substring_from_byte_offset(0, *index));
+            string = MUST(string.substring_from_byte_offset(0, *index));
    }

    // 10. Let int be result.[[IntegerDigitsCount]].
@ -507,10 +507,10 @@ ThrowCompletionOr<FormatResult> format_numeric_to_string(VM& vm, NumberFormatBas
    // 12. If int < minInteger, then
    if (digits < min_integer) {
        // a. Let forwardZeros be the String consisting of minInteger - int occurrences of the code unit 0x0030 (DIGIT ZERO).
-        auto forward_zeros = TRY_OR_THROW_OOM(vm, String::repeated('0', min_integer - digits));
+        auto forward_zeros = MUST(String::repeated('0', min_integer - digits));

        // b. Set string to the string-concatenation of forwardZeros and string.
-        string = TRY_OR_THROW_OOM(vm, String::formatted("{}{}", forward_zeros, string));
+        string = MUST(String::formatted("{}{}", forward_zeros, string));
    }

    // 13. If isNegative is true, then
@ -523,11 +523,11 @@ ThrowCompletionOr<FormatResult> format_numeric_to_string(VM& vm, NumberFormatBas
    }

    // 14. Return the Record { [[RoundedNumber]]: x, [[FormattedString]]: string }.
-    return FormatResult { move(string), move(number) };
+    return { move(string), move(number) };
 }

 // 15.5.4 PartitionNumberPattern ( numberFormat, x ), https://tc39.es/ecma402/#sec-partitionnumberpattern
-ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, NumberFormat& number_format, MathematicalValue number)
+Vector<PatternPartition> partition_number_pattern(VM& vm, NumberFormat& number_format, MathematicalValue number)
 {
    // 1. Let exponent be 0.
    int exponent = 0;
@ -538,13 +538,13 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
    if (number.is_nan()) {
        // a. Let n be an implementation- and locale-dependent (ILD) String value indicating the NaN value.
        auto symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::NaN).value_or("NaN"sv);
-        formatted_string = TRY_OR_THROW_OOM(vm, String::from_utf8(symbol));
+        formatted_string = MUST(String::from_utf8(symbol));
    }
    // 3. Else if x is positive-infinity, then
    else if (number.is_positive_infinity()) {
        // a. Let n be an ILD String value indicating positive infinity.
        auto symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Infinity).value_or("infinity"sv);
-        formatted_string = TRY_OR_THROW_OOM(vm, String::from_utf8(symbol));
+        formatted_string = MUST(String::from_utf8(symbol));
    }
    // 4. Else if x is negative-infinity, then
    else if (number.is_negative_infinity()) {
@ -552,7 +552,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
        // NOTE: The CLDR does not contain unique strings for negative infinity. The negative sign will
        //       be inserted by the pattern returned from GetNumberFormatPattern.
        auto symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Infinity).value_or("infinity"sv);
-        formatted_string = TRY_OR_THROW_OOM(vm, String::from_utf8(symbol));
+        formatted_string = MUST(String::from_utf8(symbol));
    }
    // 5. Else,
    else {
@ -566,14 +566,14 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
                number = number.multiplied_by(100);

            // iii. Let exponent be ComputeExponent(numberFormat, x).
-            exponent = MUST_OR_THROW_OOM(compute_exponent(vm, number_format, number));
+            exponent = compute_exponent(number_format, number);

            // iv. Let x be x × 10^-exponent.
            number = number.multiplied_by_power(-exponent);
        }

        // b. Let formatNumberResult be FormatNumericToString(numberFormat, x).
-        auto format_number_result = MUST_OR_THROW_OOM(format_numeric_to_string(vm, number_format, move(number)));
+        auto format_number_result = format_numeric_to_string(number_format, move(number));

        // c. Let n be formatNumberResult.[[FormattedString]].
        formatted_string = move(format_number_result.formatted_string);
@ -585,9 +585,9 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
    ::Locale::NumberFormat found_pattern {};

    // 6. Let pattern be GetNumberFormatPattern(numberFormat, x).
-    auto pattern = MUST_OR_THROW_OOM(get_number_format_pattern(vm, number_format, number, found_pattern));
+    auto pattern = get_number_format_pattern(vm, number_format, number, found_pattern);
    if (!pattern.has_value())
-        return Vector<PatternPartition> {};
+        return {};

    // 7. Let result be a new empty List.
    Vector<PatternPartition> result;
@ -603,15 +603,15 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
        // b. If p is "literal", then
        if (part == "literal"sv) {
            // i. Append a new Record { [[Type]]: "literal", [[Value]]: patternPart.[[Value]] } as the last element of result.
-            TRY_OR_THROW_OOM(vm, result.try_append({ "literal"sv, move(pattern_part.value) }));
+            result.append({ "literal"sv, move(pattern_part.value) });
        }

        // c. Else if p is equal to "number", then
        else if (part == "number"sv) {
            // i. Let notationSubParts be PartitionNotationSubPattern(numberFormat, x, n, exponent).
-            auto notation_sub_parts = MUST_OR_THROW_OOM(partition_notation_sub_pattern(vm, number_format, number, formatted_string, exponent));
+            auto notation_sub_parts = partition_notation_sub_pattern(number_format, number, formatted_string, exponent);
            // ii. Append all elements of notationSubParts to result.
-            TRY_OR_THROW_OOM(vm, result.try_extend(move(notation_sub_parts)));
+            result.extend(move(notation_sub_parts));
        }

        // d. Else if p is equal to "plusSign", then
@ -619,7 +619,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
            // i. Let plusSignSymbol be the ILND String representing the plus sign.
            auto plus_sign_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::PlusSign).value_or("+"sv);
            // ii. Append a new Record { [[Type]]: "plusSign", [[Value]]: plusSignSymbol } as the last element of result.
-            TRY_OR_THROW_OOM(vm, result.try_append({ "plusSign"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(plus_sign_symbol)) }));
+            result.append({ "plusSign"sv, MUST(String::from_utf8(plus_sign_symbol)) });
        }

        // e. Else if p is equal to "minusSign", then
@ -627,7 +627,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
            // i. Let minusSignSymbol be the ILND String representing the minus sign.
            auto minus_sign_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::MinusSign).value_or("-"sv);
            // ii. Append a new Record { [[Type]]: "minusSign", [[Value]]: minusSignSymbol } as the last element of result.
-            TRY_OR_THROW_OOM(vm, result.try_append({ "minusSign"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(minus_sign_symbol)) }));
+            result.append({ "minusSign"sv, MUST(String::from_utf8(minus_sign_symbol)) });
        }

        // f. Else if p is equal to "percentSign" and numberFormat.[[Style]] is "percent", then
@ -635,7 +635,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
            // i. Let percentSignSymbol be the ILND String representing the percent sign.
            auto percent_sign_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::PercentSign).value_or("%"sv);
            // ii. Append a new Record { [[Type]]: "percentSign", [[Value]]: percentSignSymbol } as the last element of result.
-            TRY_OR_THROW_OOM(vm, result.try_append({ "percentSign"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(percent_sign_symbol)) }));
+            result.append({ "percentSign"sv, MUST(String::from_utf8(percent_sign_symbol)) });
        }

        // g. Else if p is equal to "unitPrefix" and numberFormat.[[Style]] is "unit", then
@ -652,7 +652,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
            auto unit_identifier = found_pattern.identifiers[*identifier_index];

            // iv. Append a new Record { [[Type]]: "unit", [[Value]]: mu } as the last element of result.
-            TRY_OR_THROW_OOM(vm, result.try_append({ "unit"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(unit_identifier)) }));
+            result.append({ "unit"sv, MUST(String::from_utf8(unit_identifier)) });
        }

        // i. Else if p is equal to "currencyCode" and numberFormat.[[Style]] is "currency", then
@ -664,7 +664,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
        //       display / plurality lookups more than once.
        else if ((part == "currency"sv) && (number_format.style() == NumberFormat::Style::Currency)) {
            auto currency = number_format.resolve_currency_display();
-            TRY_OR_THROW_OOM(vm, result.try_append({ "currency"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(currency)) }));
+            result.append({ "currency"sv, MUST(String::from_utf8(currency)) });
        }

        // l. Else,
@ -681,29 +681,23 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
    return result;
 }

-static ThrowCompletionOr<Vector<String>> separate_integer_into_groups(VM& vm, ::Locale::NumberGroupings const& grouping_sizes, String integer, NumberFormat::UseGrouping use_grouping)
+static Vector<String> separate_integer_into_groups(::Locale::NumberGroupings const& grouping_sizes, String integer, NumberFormat::UseGrouping use_grouping)
 {
-    auto default_group = [&]() -> ThrowCompletionOr<Vector<String>> {
-        Vector<String> groups;
-        TRY_OR_THROW_OOM(vm, groups.try_append(move(integer)));
-        return groups;
-    };
-
    auto utf8_integer = integer.code_points();
    if (utf8_integer.length() <= grouping_sizes.primary_grouping_size)
-        return default_group();
+        return { move(integer) };

    size_t index = utf8_integer.length() - grouping_sizes.primary_grouping_size;

    switch (use_grouping) {
    case NumberFormat::UseGrouping::Min2:
        if (utf8_integer.length() < 5)
-            return default_group();
+            return { move(integer) };
        break;

    case NumberFormat::UseGrouping::Auto:
        if (index < grouping_sizes.minimum_grouping_digits)
-            return default_group();
+            return { move(integer) };
        break;

    case NumberFormat::UseGrouping::Always:
@ -715,55 +709,53 @@ static ThrowCompletionOr<Vector<String>> separate_integer_into_groups(VM& vm, ::

    Vector<String> groups;

-    auto add_group = [&](size_t index, size_t length) -> ThrowCompletionOr<void> {
+    auto add_group = [&](size_t index, size_t length) {
        length = utf8_integer.unicode_substring_view(index, length).byte_length();
        index = utf8_integer.byte_offset_of(index);

-        auto group = TRY_OR_THROW_OOM(vm, integer.substring_from_byte_offset_with_shared_superstring(index, length));
-        TRY_OR_THROW_OOM(vm, groups.try_prepend(move(group)));
-
-        return {};
+        auto group = MUST(integer.substring_from_byte_offset_with_shared_superstring(index, length));
+        groups.prepend(move(group));
    };

-    MUST_OR_THROW_OOM(add_group(index, grouping_sizes.primary_grouping_size));
+    add_group(index, grouping_sizes.primary_grouping_size);

    while (index > grouping_sizes.secondary_grouping_size) {
        index -= grouping_sizes.secondary_grouping_size;
-        MUST_OR_THROW_OOM(add_group(index, grouping_sizes.secondary_grouping_size));
+        add_group(index, grouping_sizes.secondary_grouping_size);
    }

    if (index > 0)
-        MUST_OR_THROW_OOM(add_group(0, index));
+        add_group(0, index);

    return groups;
 }

 // 15.5.5 PartitionNotationSubPattern ( numberFormat, x, n, exponent ), https://tc39.es/ecma402/#sec-partitionnotationsubpattern
-ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& vm, NumberFormat& number_format, MathematicalValue const& number, String formatted_string, int exponent)
+Vector<PatternPartition> partition_notation_sub_pattern(NumberFormat& number_format, MathematicalValue const& number, String formatted_string, int exponent)
 {
    // 1. Let result be a new empty List.
    Vector<PatternPartition> result;

    auto grouping_sizes = ::Locale::get_number_system_groupings(number_format.data_locale(), number_format.numbering_system());
    if (!grouping_sizes.has_value())
-        return Vector<PatternPartition> {};
+        return {};

    // 2. If x is not-a-number, then
    if (number.is_nan()) {
        // a. Append a new Record { [[Type]]: "nan", [[Value]]: n } as the last element of result.
-        TRY_OR_THROW_OOM(vm, result.try_append({ "nan"sv, move(formatted_string) }));
+        result.append({ "nan"sv, move(formatted_string) });
    }
    // 3. Else if x is positive-infinity or negative-infinity, then
    else if (number.is_positive_infinity() || number.is_negative_infinity()) {
        // a. Append a new Record { [[Type]]: "infinity", [[Value]]: n } as the last element of result.
-        TRY_OR_THROW_OOM(vm, result.try_append({ "infinity"sv, move(formatted_string) }));
+        result.append({ "infinity"sv, move(formatted_string) });
    }
    // 4. Else,
    else {
        // a. Let notationSubPattern be GetNotationSubPattern(numberFormat, exponent).
        auto notation_sub_pattern = get_notation_sub_pattern(number_format, exponent);
        if (!notation_sub_pattern.has_value())
-            return Vector<PatternPartition> {};
+            return {};

        // b. Let patternParts be PartitionPattern(notationSubPattern).
        auto pattern_parts = partition_pattern(*notation_sub_pattern);
@ -776,7 +768,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
            // ii. If p is "literal", then
            if (part == "literal"sv) {
                // 1. Append a new Record { [[Type]]: "literal", [[Value]]: patternPart.[[Value]] } as the last element of result.
-                TRY_OR_THROW_OOM(vm, result.try_append({ "literal"sv, move(pattern_part.value) }));
+                result.append({ "literal"sv, move(pattern_part.value) });
            }
            // iii. Else if p is equal to "number", then
            else if (part == "number"sv) {
@ -807,10 +799,10 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                // 4. If decimalSepIndex > 0, then
                if (decimal_sep_index.has_value() && (*decimal_sep_index > 0)) {
                    // a. Let integer be the substring of n from position 0, inclusive, to position decimalSepIndex, exclusive.
-                    integer = TRY_OR_THROW_OOM(vm, formatted_string.substring_from_byte_offset_with_shared_superstring(0, *decimal_sep_index));
+                    integer = MUST(formatted_string.substring_from_byte_offset_with_shared_superstring(0, *decimal_sep_index));

                    // b. Let fraction be the substring of n from position decimalSepIndex, exclusive, to the end of n.
-                    fraction = TRY_OR_THROW_OOM(vm, formatted_string.substring_from_byte_offset_with_shared_superstring(*decimal_sep_index + 1));
+                    fraction = MUST(formatted_string.substring_from_byte_offset_with_shared_superstring(*decimal_sep_index + 1));
                }
                // 5. Else,
                else {
@ -822,7 +814,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                // 6. If the numberFormat.[[UseGrouping]] is false, then
                if (number_format.use_grouping() == NumberFormat::UseGrouping::False) {
                    // a. Append a new Record { [[Type]]: "integer", [[Value]]: integer } as the last element of result.
-                    TRY_OR_THROW_OOM(vm, result.try_append({ "integer"sv, move(integer) }));
+                    result.append({ "integer"sv, move(integer) });
                }
                // 7. Else,
                else {
@ -830,7 +822,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                    auto group_sep_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Group).value_or(","sv);

                    // b. Let groups be a List whose elements are, in left to right order, the substrings defined by ILND set of locations within the integer, which may depend on the value of numberFormat.[[UseGrouping]].
-                    auto groups = MUST_OR_THROW_OOM(separate_integer_into_groups(vm, *grouping_sizes, move(integer), number_format.use_grouping()));
+                    auto groups = separate_integer_into_groups(*grouping_sizes, move(integer), number_format.use_grouping());

                    // c. Assert: The number of elements in groups List is greater than 0.
                    VERIFY(!groups.is_empty());
@ -841,12 +833,12 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                        auto integer_group = groups.take_first();

                        // ii. Append a new Record { [[Type]]: "integer", [[Value]]: integerGroup } as the last element of result.
-                        TRY_OR_THROW_OOM(vm, result.try_append({ "integer"sv, move(integer_group) }));
+                        result.append({ "integer"sv, move(integer_group) });

                        // iii. If groups List is not empty, then
                        if (!groups.is_empty()) {
                            // i. Append a new Record { [[Type]]: "group", [[Value]]: groupSepSymbol } as the last element of result.
-                            TRY_OR_THROW_OOM(vm, result.try_append({ "group"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(group_sep_symbol)) }));
+                            result.append({ "group"sv, MUST(String::from_utf8(group_sep_symbol)) });
                        }
                    }
                }
@ -856,9 +848,9 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                    // a. Let decimalSepSymbol be the ILND String representing the decimal separator.
                    auto decimal_sep_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Decimal).value_or("."sv);
                    // b. Append a new Record { [[Type]]: "decimal", [[Value]]: decimalSepSymbol } as the last element of result.
-                    TRY_OR_THROW_OOM(vm, result.try_append({ "decimal"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(decimal_sep_symbol)) }));
+                    result.append({ "decimal"sv, MUST(String::from_utf8(decimal_sep_symbol)) });
                    // c. Append a new Record { [[Type]]: "fraction", [[Value]]: fraction } as the last element of result.
-                    TRY_OR_THROW_OOM(vm, result.try_append({ "fraction"sv, fraction.release_value() }));
+                    result.append({ "fraction"sv, fraction.release_value() });
                }
            }
            // iv. Else if p is equal to "compactSymbol", then
@ -873,14 +865,14 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                auto compact_identifier = number_format.compact_format().identifiers[*identifier_index];

                // 2. Append a new Record { [[Type]]: "compact", [[Value]]: compactSymbol } as the last element of result.
-                TRY_OR_THROW_OOM(vm, result.try_append({ "compact"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(compact_identifier)) }));
+                result.append({ "compact"sv, MUST(String::from_utf8(compact_identifier)) });
            }
            // vi. Else if p is equal to "scientificSeparator", then
            else if (part == "scientificSeparator"sv) {
                // 1. Let scientificSeparator be the ILND String representing the exponent separator.
                auto scientific_separator = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Exponential).value_or("E"sv);
                // 2. Append a new Record { [[Type]]: "exponentSeparator", [[Value]]: scientificSeparator } as the last element of result.
-                TRY_OR_THROW_OOM(vm, result.try_append({ "exponentSeparator"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(scientific_separator)) }));
+                result.append({ "exponentSeparator"sv, MUST(String::from_utf8(scientific_separator)) });
            }
            // vii. Else if p is equal to "scientificExponent", then
            else if (part == "scientificExponent"sv) {
@ -890,7 +882,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                    auto minus_sign_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::MinusSign).value_or("-"sv);

                    // b. Append a new Record { [[Type]]: "exponentMinusSign", [[Value]]: minusSignSymbol } as the last element of result.
-                    TRY_OR_THROW_OOM(vm, result.try_append({ "exponentMinusSign"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(minus_sign_symbol)) }));
+                    result.append({ "exponentMinusSign"sv, MUST(String::from_utf8(minus_sign_symbol)) });

                    // c. Let exponent be -exponent.
                    exponent *= -1;
@ -898,14 +890,14 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v

                // 2. Let exponentResult be ToRawFixed(exponent, 0, 0, 1, undefined).
                auto exponent_value = MathematicalValue { static_cast<double>(exponent) };
-                auto exponent_result = MUST_OR_THROW_OOM(to_raw_fixed(vm, exponent_value, 0, 0, 1, {}));
+                auto exponent_result = to_raw_fixed(exponent_value, 0, 0, 1, {});

                // FIXME: The spec does not say to do this, but all of major engines perform this replacement.
                //        Without this, formatting with non-Latin numbering systems will produce non-localized results.
                exponent_result.formatted_string = ::Locale::replace_digits_for_number_system(number_format.numbering_system(), exponent_result.formatted_string);

                // 3. Append a new Record { [[Type]]: "exponentInteger", [[Value]]: exponentResult.[[FormattedString]] } as the last element of result.
-                TRY_OR_THROW_OOM(vm, result.try_append({ "exponentInteger"sv, move(exponent_result.formatted_string) }));
+                result.append({ "exponentInteger"sv, move(exponent_result.formatted_string) });
            }
            // viii. Else,
            else {
@ -923,31 +915,31 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
 }

 // 15.5.6 FormatNumeric ( numberFormat, x ), https://tc39.es/ecma402/#sec-formatnumber
-ThrowCompletionOr<String> format_numeric(VM& vm, NumberFormat& number_format, MathematicalValue number)
+String format_numeric(VM& vm, NumberFormat& number_format, MathematicalValue number)
 {
    // 1. Let parts be ? PartitionNumberPattern(numberFormat, x).
-    auto parts = TRY(partition_number_pattern(vm, number_format, move(number)));
+    auto parts = partition_number_pattern(vm, number_format, move(number));

    // 2. Let result be the empty String.
-    ThrowableStringBuilder result(vm);
+    StringBuilder result;

    // 3. For each Record { [[Type]], [[Value]] } part in parts, do
    for (auto& part : parts) {
        // a. Set result to the string-concatenation of result and part.[[Value]].
-        TRY(result.append(part.value));
+        result.append(part.value);
    }

    // 4. Return result.
-    return result.to_string();
+    return MUST(result.to_string());
 }

 // 15.5.7 FormatNumericToParts ( numberFormat, x ), https://tc39.es/ecma402/#sec-formatnumbertoparts
-ThrowCompletionOr<Array*> format_numeric_to_parts(VM& vm, NumberFormat& number_format, MathematicalValue number)
+NonnullGCPtr<Array> format_numeric_to_parts(VM& vm, NumberFormat& number_format, MathematicalValue number)
 {
    auto& realm = *vm.current_realm();

    // 1. Let parts be ? PartitionNumberPattern(numberFormat, x).
-    auto parts = TRY(partition_number_pattern(vm, number_format, move(number)));
+    auto parts = partition_number_pattern(vm, number_format, move(number));

    // 2. Let result be ! ArrayCreate(0).
    auto result = MUST(Array::create(realm, 0));
@ -974,10 +966,10 @@ ThrowCompletionOr<Array*> format_numeric_to_parts(VM& vm, NumberFormat& number_f
    }

    // 5. Return result.
-    return result.ptr();
+    return result;
 }

-static ErrorOr<String> cut_trailing_zeroes(StringView string, int cut)
+static String cut_trailing_zeroes(StringView string, int cut)
 {
    // These steps are exactly the same between ToRawPrecision and ToRawFixed.

@ -996,7 +988,7 @@ static ErrorOr<String> cut_trailing_zeroes(StringView string, int cut)
        string = string.substring_view(0, string.length() - 1);
    }

-    return String::from_utf8(string);
+    return MUST(String::from_utf8(string));
 }

 enum class PreferredResult {
@ -1047,7 +1039,7 @@ static RawPrecisionResult to_raw_precision_function(MathematicalValue const& num
 }

 // 15.5.8 ToRawPrecision ( x, minPrecision, maxPrecision ), https://tc39.es/ecma402/#sec-torawprecision
-ThrowCompletionOr<RawFormatResult> to_raw_precision(VM& vm, MathematicalValue const& number, int min_precision, int max_precision, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode)
+RawFormatResult to_raw_precision(MathematicalValue const& number, int min_precision, int max_precision, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode)
 {
    RawFormatResult result {};

@ -1058,7 +1050,7 @@ ThrowCompletionOr<RawFormatResult> to_raw_precision(VM& vm, MathematicalValue co
    // 2. If x = 0, then
    if (number.is_zero()) {
        // a. Let m be the String consisting of p occurrences of the code unit 0x0030 (DIGIT ZERO).
-        result.formatted_string = TRY_OR_THROW_OOM(vm, String::repeated('0', precision));
+        result.formatted_string = MUST(String::repeated('0', precision));

        // b. Let e be 0.
        exponent = 0;
@ -1109,11 +1101,10 @@ ThrowCompletionOr<RawFormatResult> to_raw_precision(VM& vm, MathematicalValue co
    // 4. If e ≥ (p – 1), then
    if (exponent >= (precision - 1)) {
        // a. Set m to the string-concatenation of m and e - p + 1 occurrences of the code unit 0x0030 (DIGIT ZERO).
-        result.formatted_string = TRY_OR_THROW_OOM(vm,
-            String::formatted(
+        result.formatted_string = MUST(String::formatted(
            "{}{}",
            result.formatted_string,
-                TRY_OR_THROW_OOM(vm, String::repeated('0', exponent - precision + 1))));
+            MUST(String::repeated('0', exponent - precision + 1))));

        // b. Let int be e + 1.
        result.digits = exponent + 1;
@ -1121,8 +1112,7 @@ ThrowCompletionOr<RawFormatResult> to_raw_precision(VM& vm, MathematicalValue co
    // 5. Else if e ≥ 0, then
    else if (exponent >= 0) {
        // a. Set m to the string-concatenation of the first e + 1 code units of m, the code unit 0x002E (FULL STOP), and the remaining p - (e + 1) code units of m.
-        result.formatted_string = TRY_OR_THROW_OOM(vm,
-            String::formatted(
+        result.formatted_string = MUST(String::formatted(
            "{}.{}",
            result.formatted_string.bytes_as_string_view().substring_view(0, exponent + 1),
            result.formatted_string.bytes_as_string_view().substring_view(exponent + 1)));
@ -1134,10 +1124,9 @@ ThrowCompletionOr<RawFormatResult> to_raw_precision(VM& vm, MathematicalValue co
    else {
        // a. Assert: e < 0.
        // b. Set m to the string-concatenation of "0.", -(e + 1) occurrences of the code unit 0x0030 (DIGIT ZERO), and m.
-        result.formatted_string = TRY_OR_THROW_OOM(vm,
-            String::formatted(
+        result.formatted_string = MUST(String::formatted(
            "0.{}{}",
-                TRY_OR_THROW_OOM(vm, String::repeated('0', -1 * (exponent + 1))),
+            MUST(String::repeated('0', -1 * (exponent + 1))),
            result.formatted_string));

        // c. Let int be 1.
@ -1150,7 +1139,7 @@ ThrowCompletionOr<RawFormatResult> to_raw_precision(VM& vm, MathematicalValue co
        int cut = max_precision - min_precision;

        // Steps 8b-8c are implemented by cut_trailing_zeroes.
-        result.formatted_string = TRY_OR_THROW_OOM(vm, cut_trailing_zeroes(result.formatted_string, cut));
+        result.formatted_string = cut_trailing_zeroes(result.formatted_string, cut);
    }

    // 8. Return the Record { [[FormattedString]]: m, [[RoundedNumber]]: xFinal, [[IntegerDigitsCount]]: int, [[RoundingMagnitude]]: e–p+1 }.
@ -1210,7 +1199,7 @@ static RawFixedResult to_raw_fixed_function(MathematicalValue const& number, int
 }

 // 15.5.9 ToRawFixed ( x, minInteger, minFraction, maxFraction ), https://tc39.es/ecma402/#sec-torawfixed
-ThrowCompletionOr<RawFormatResult> to_raw_fixed(VM& vm, MathematicalValue const& number, int min_fraction, int max_fraction, int rounding_increment, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode)
+RawFormatResult to_raw_fixed(MathematicalValue const& number, int min_fraction, int max_fraction, int rounding_increment, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode)
 {
    RawFormatResult result {};

@ -1256,10 +1245,10 @@ ThrowCompletionOr<RawFormatResult> to_raw_fixed(VM& vm, MathematicalValue const&
        // b. If k ≤ f, then
        if (decimals <= static_cast<size_t>(fraction)) {
            // i. Let z be the String value consisting of f + 1 - k occurrences of the code unit 0x0030 (DIGIT ZERO).
-            auto zeroes = TRY_OR_THROW_OOM(vm, String::repeated('0', fraction + 1 - decimals));
+            auto zeroes = MUST(String::repeated('0', fraction + 1 - decimals));

            // ii. Let m be the string-concatenation of z and m.
-            result.formatted_string = TRY_OR_THROW_OOM(vm, String::formatted("{}{}", zeroes, result.formatted_string));
+            result.formatted_string = MUST(String::formatted("{}{}", zeroes, result.formatted_string));

            // iii. Let k be f + 1.
            decimals = fraction + 1;
@ -1270,7 +1259,7 @@ ThrowCompletionOr<RawFormatResult> to_raw_fixed(VM& vm, MathematicalValue const&
        auto b = result.formatted_string.bytes_as_string_view().substring_view(decimals - fraction, fraction);

        // d. Let m be the string-concatenation of a, ".", and b.
-        result.formatted_string = TRY_OR_THROW_OOM(vm, String::formatted("{}.{}", a, b));
+        result.formatted_string = MUST(String::formatted("{}.{}", a, b));

        // e. Let int be the length of a.
        result.digits = a.length();
@ -1284,7 +1273,7 @@ ThrowCompletionOr<RawFormatResult> to_raw_fixed(VM& vm, MathematicalValue const&
    int cut = max_fraction - min_fraction;

    // Steps 11-12 are implemented by cut_trailing_zeroes.
-    result.formatted_string = TRY_OR_THROW_OOM(vm, cut_trailing_zeroes(result.formatted_string, cut));
+    result.formatted_string = cut_trailing_zeroes(result.formatted_string, cut);

    // 13. Return the Record { [[FormattedString]]: m, [[RoundedNumber]]: xFinal, [[IntegerDigitsCount]]: int, [[RoundingMagnitude]]: –f }.
    result.rounding_magnitude = -fraction;
@ -1299,7 +1288,7 @@ enum class NumberCategory {
 };

 // 15.5.11 GetNumberFormatPattern ( numberFormat, x ), https://tc39.es/ecma402/#sec-getnumberformatpattern
-ThrowCompletionOr<Optional<Variant<StringView, String>>> get_number_format_pattern(VM& vm, NumberFormat& number_format, MathematicalValue const& number, ::Locale::NumberFormat& found_pattern)
+Optional<Variant<StringView, String>> get_number_format_pattern(VM& vm, NumberFormat& number_format, MathematicalValue const& number, ::Locale::NumberFormat& found_pattern)
 {
    // 1. Let localeData be %NumberFormat%.[[LocaleData]].
    // 2. Let dataLocale be numberFormat.[[DataLocale]].
@ -1326,7 +1315,7 @@ ThrowCompletionOr<Optional<Variant<StringView, String>>> get_number_format_patte
        // e. Let patterns be patterns.[[<unit>]].
        // f. Let patterns be patterns.[[<unitDisplay>]].
        auto formats = ::Locale::get_unit_formats(number_format.data_locale(), number_format.unit(), number_format.unit_display());
-        auto plurality = MUST_OR_THROW_OOM(resolve_plural(vm, number_format, ::Locale::PluralForm::Cardinal, number.to_value(vm)));
+        auto plurality = resolve_plural(number_format, ::Locale::PluralForm::Cardinal, number.to_value(vm));

        if (auto it = formats.find_if([&](auto& p) { return p.plurality == plurality.plural_category; }); it != formats.end())
            patterns = move(*it);
@ -1349,7 +1338,7 @@ ThrowCompletionOr<Optional<Variant<StringView, String>>> get_number_format_patte
        // Handling of other [[CurrencyDisplay]] options will occur after [[SignDisplay]].
        if (number_format.currency_display() == NumberFormat::CurrencyDisplay::Name) {
            auto formats = ::Locale::get_compact_number_system_formats(number_format.data_locale(), number_format.numbering_system(), ::Locale::CompactNumberFormatType::CurrencyUnit);
-            auto plurality = MUST_OR_THROW_OOM(resolve_plural(vm, number_format, ::Locale::PluralForm::Cardinal, number.to_value(vm)));
+            auto plurality = resolve_plural(number_format, ::Locale::PluralForm::Cardinal, number.to_value(vm));

            if (auto it = formats.find_if([&](auto& p) { return p.plurality == plurality.plural_category; }); it != formats.end()) {
                patterns = move(*it);
@ -1380,7 +1369,7 @@ ThrowCompletionOr<Optional<Variant<StringView, String>>> get_number_format_patte
    }

    if (!patterns.has_value())
-        return OptionalNone {};
+        return {};

    NumberCategory category;

@ -1556,7 +1545,7 @@ Optional<StringView> get_notation_sub_pattern(NumberFormat& number_format, int e
 }

 // 15.5.13 ComputeExponent ( numberFormat, x ), https://tc39.es/ecma402/#sec-computeexponent
-ThrowCompletionOr<int> compute_exponent(VM& vm, NumberFormat& number_format, MathematicalValue number)
+int compute_exponent(NumberFormat& number_format, MathematicalValue number)
 {
    // 1. If x = 0, then
    if (number.is_zero()) {
@ -1580,7 +1569,7 @@ ThrowCompletionOr<int> compute_exponent(VM& vm, NumberFormat& number_format, Mat
    number = number.multiplied_by_power(-exponent);

    // 6. Let formatNumberResult be FormatNumericToString(numberFormat, x).
-    auto format_number_result = MUST_OR_THROW_OOM(format_numeric_to_string(vm, number_format, move(number)));
+    auto format_number_result = format_numeric_to_string(number_format, move(number));

    // 7. If formatNumberResult.[[RoundedNumber]] = 0, then
    if (format_number_result.rounded_number.is_zero()) {
@ -1809,20 +1798,20 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_number_range_pat
    Vector<PatternPartitionWithSource> result;

    // 3. Let xResult be ? PartitionNumberPattern(numberFormat, x).
-    auto raw_start_result = TRY(partition_number_pattern(vm, number_format, move(start)));
+    auto raw_start_result = partition_number_pattern(vm, number_format, move(start));
    auto start_result = PatternPartitionWithSource::create_from_parent_list(move(raw_start_result));

    // 4. Let yResult be ? PartitionNumberPattern(numberFormat, y).
-    auto raw_end_result = TRY(partition_number_pattern(vm, number_format, move(end)));
+    auto raw_end_result = partition_number_pattern(vm, number_format, move(end));
    auto end_result = PatternPartitionWithSource::create_from_parent_list(move(raw_end_result));

    // 5. If ! FormatNumeric(numberFormat, x) is equal to ! FormatNumeric(numberFormat, y), then
-    auto formatted_start = MUST_OR_THROW_OOM(format_numeric(vm, number_format, start));
-    auto formatted_end = MUST_OR_THROW_OOM(format_numeric(vm, number_format, end));
+    auto formatted_start = format_numeric(vm, number_format, start);
+    auto formatted_end = format_numeric(vm, number_format, end);

    if (formatted_start == formatted_end) {
        // a. Let appxResult be ? FormatApproximately(numberFormat, xResult).
-        auto approximate_result = TRY(format_approximately(vm, number_format, move(start_result)));
+        auto approximate_result = format_approximately(number_format, move(start_result));

        // b. For each r in appxResult, do
        for (auto& result : approximate_result) {
@ -1835,7 +1824,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_number_range_pat
    }

    // 6. For each element r in xResult, do
-    TRY_OR_THROW_OOM(vm, result.try_ensure_capacity(start_result.size()));
+    result.ensure_capacity(start_result.size());

    for (auto& start_part : start_result) {
        // a. Append a new Record { [[Type]]: r.[[Type]], [[Value]]: r.[[Value]], [[Source]]: "startRange" } as the last element of result.
@ -1856,12 +1845,12 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_number_range_pat
    part.type = "literal"sv;
    part.value = range_separator.has_value()
        ? range_separator.release_value()
-        : TRY_OR_THROW_OOM(vm, String::from_utf8(range_separator_symbol));
+        : MUST(String::from_utf8(range_separator_symbol));
    part.source = "shared"sv;
-    TRY_OR_THROW_OOM(vm, result.try_append(move(part)));
+    result.append(move(part));

    // 9. For each element r in yResult, do
-    TRY_OR_THROW_OOM(vm, result.try_ensure_capacity(result.size() + end_result.size()));
+    result.ensure_capacity(result.size() + end_result.size());

    for (auto& end_part : end_result) {
        // a. Append a new Record { [[Type]]: r.[[Type]], [[Value]]: r.[[Value]], [[Source]]: "endRange" } as the last element of result.
@ -1878,7 +1867,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_number_range_pat
 }

 // 15.5.20 FormatApproximately ( numberFormat, result ), https://tc39.es/ecma402/#sec-formatapproximately
-ThrowCompletionOr<Vector<PatternPartitionWithSource>> format_approximately(VM& vm, NumberFormat& number_format, Vector<PatternPartitionWithSource> result)
+Vector<PatternPartitionWithSource> format_approximately(NumberFormat& number_format, Vector<PatternPartitionWithSource> result)
 {
    // 1. Let approximatelySign be an ILND String value used to signify that a number is approximate.
    auto approximately_sign = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::ApproximatelySign);
@ -1887,11 +1876,11 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> format_approximately(VM& v
    if (approximately_sign.has_value() && !approximately_sign->is_empty()) {
        PatternPartitionWithSource partition;
        partition.type = "approximatelySign"sv;
-        partition.value = TRY_OR_THROW_OOM(vm, String::from_utf8(*approximately_sign));
+        partition.value = MUST(String::from_utf8(*approximately_sign));

-        TRY_OR_THROW_OOM(vm, result.try_insert_before_matching(move(partition), [](auto const& part) {
+        result.insert_before_matching(move(partition), [](auto const& part) {
            return part.type.is_one_of("integer"sv, "decimal"sv, "plusSign"sv, "minusSign"sv, "percentSign"sv, "currency"sv);
-        }));
+        });
    }

    // 3. Return result.
@ -1912,20 +1901,20 @@ ThrowCompletionOr<String> format_numeric_range(VM& vm, NumberFormat& number_form
    auto parts = TRY(partition_number_range_pattern(vm, number_format, move(start), move(end)));

    // 2. Let result be the empty String.
-    ThrowableStringBuilder result(vm);
+    StringBuilder result;

    // 3. For each part in parts, do
    for (auto& part : parts) {
        // a. Set result to the string-concatenation of result and part.[[Value]].
-        TRY(result.append(part.value));
+        result.append(part.value);
    }

    // 4. Return result.
-    return result.to_string();
+    return MUST(result.to_string());
 }

 // 15.5.23 FormatNumericRangeToParts ( numberFormat, x, y ), https://tc39.es/ecma402/#sec-formatnumericrangetoparts
-ThrowCompletionOr<Array*> format_numeric_range_to_parts(VM& vm, NumberFormat& number_format, MathematicalValue start, MathematicalValue end)
+ThrowCompletionOr<NonnullGCPtr<Array>> format_numeric_range_to_parts(VM& vm, NumberFormat& number_format, MathematicalValue start, MathematicalValue end)
 {
    auto& realm = *vm.current_realm();

@ -1960,7 +1949,7 @@ ThrowCompletionOr<Array*> format_numeric_range_to_parts(VM& vm, NumberFormat& nu
    }

    // 5. Return result.
-    return result.ptr();
+    return result;
 }

 }
--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.h
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.h
@ -222,7 +222,7 @@ public:
    void set_unit_display(StringView unit_display) { m_unit_display = ::Locale::style_from_string(unit_display); }

    UseGrouping use_grouping() const { return m_use_grouping; }
-    ThrowCompletionOr<Value> use_grouping_to_value(VM&) const;
+    Value use_grouping_to_value(VM&) const;
    void set_use_grouping(StringOrBoolean const& use_grouping);

    Notation notation() const { return m_notation; }
@ -288,24 +288,24 @@ enum class RoundingDecision {
 };

 int currency_digits(StringView currency);
-ThrowCompletionOr<FormatResult> format_numeric_to_string(VM&, NumberFormatBase const& intl_object, MathematicalValue number);
-ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM&, NumberFormat&, MathematicalValue number);
-ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM&, NumberFormat&, MathematicalValue const& number, String formatted_string, int exponent);
-ThrowCompletionOr<String> format_numeric(VM&, NumberFormat&, MathematicalValue number);
-ThrowCompletionOr<Array*> format_numeric_to_parts(VM&, NumberFormat&, MathematicalValue number);
-ThrowCompletionOr<RawFormatResult> to_raw_precision(VM&, MathematicalValue const& number, int min_precision, int max_precision, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode);
-ThrowCompletionOr<RawFormatResult> to_raw_fixed(VM&, MathematicalValue const& number, int min_fraction, int max_fraction, int rounding_increment, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode);
-ThrowCompletionOr<Optional<Variant<StringView, String>>> get_number_format_pattern(VM&, NumberFormat&, MathematicalValue const& number, ::Locale::NumberFormat& found_pattern);
+FormatResult format_numeric_to_string(NumberFormatBase const& intl_object, MathematicalValue number);
+Vector<PatternPartition> partition_number_pattern(VM&, NumberFormat&, MathematicalValue number);
+Vector<PatternPartition> partition_notation_sub_pattern(NumberFormat&, MathematicalValue const& number, String formatted_string, int exponent);
+String format_numeric(VM&, NumberFormat&, MathematicalValue number);
+NonnullGCPtr<Array> format_numeric_to_parts(VM&, NumberFormat&, MathematicalValue number);
+RawFormatResult to_raw_precision(MathematicalValue const& number, int min_precision, int max_precision, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode);
+RawFormatResult to_raw_fixed(MathematicalValue const& number, int min_fraction, int max_fraction, int rounding_increment, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode);
+Optional<Variant<StringView, String>> get_number_format_pattern(VM&, NumberFormat&, MathematicalValue const& number, ::Locale::NumberFormat& found_pattern);
 Optional<StringView> get_notation_sub_pattern(NumberFormat&, int exponent);
-ThrowCompletionOr<int> compute_exponent(VM&, NumberFormat&, MathematicalValue number);
+int compute_exponent(NumberFormat&, MathematicalValue number);
 int compute_exponent_for_magnitude(NumberFormat&, int magnitude);
 ThrowCompletionOr<MathematicalValue> to_intl_mathematical_value(VM&, Value value);
 NumberFormat::UnsignedRoundingMode get_unsigned_rounding_mode(NumberFormat::RoundingMode, bool is_negative);
 RoundingDecision apply_unsigned_rounding_mode(MathematicalValue const& x, MathematicalValue const& r1, MathematicalValue const& r2, NumberFormat::UnsignedRoundingMode unsigned_rounding_mode);
 ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_number_range_pattern(VM&, NumberFormat&, MathematicalValue start, MathematicalValue end);
-ThrowCompletionOr<Vector<PatternPartitionWithSource>> format_approximately(VM&, NumberFormat&, Vector<PatternPartitionWithSource> result);
+Vector<PatternPartitionWithSource> format_approximately(NumberFormat&, Vector<PatternPartitionWithSource> result);
 Vector<PatternPartitionWithSource> collapse_number_range(Vector<PatternPartitionWithSource> result);
 ThrowCompletionOr<String> format_numeric_range(VM&, NumberFormat&, MathematicalValue start, MathematicalValue end);
-ThrowCompletionOr<Array*> format_numeric_range_to_parts(VM&, NumberFormat&, MathematicalValue start, MathematicalValue end);
+ThrowCompletionOr<NonnullGCPtr<Array>> format_numeric_range_to_parts(VM&, NumberFormat&, MathematicalValue start, MathematicalValue end);

 }
--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatConstructor.cpp
@ -79,7 +79,7 @@ JS_DEFINE_NATIVE_FUNCTION(NumberFormatConstructor::supported_locales_of)
 }

 // 15.1.2 InitializeNumberFormat ( numberFormat, locales, options ), https://tc39.es/ecma402/#sec-initializenumberformat
-ThrowCompletionOr<NumberFormat*> initialize_number_format(VM& vm, NumberFormat& number_format, Value locales_value, Value options_value)
+ThrowCompletionOr<NonnullGCPtr<NumberFormat>> initialize_number_format(VM& vm, NumberFormat& number_format, Value locales_value, Value options_value)
 {
    // 1. Let requestedLocales be ? CanonicalizeLocaleList(locales).
    auto requested_locales = TRY(canonicalize_locale_list(vm, locales_value));
@ -208,7 +208,7 @@ ThrowCompletionOr<NumberFormat*> initialize_number_format(VM& vm, NumberFormat&
    number_format.set_sign_display(sign_display.as_string().utf8_string_view());

    // 31. Return numberFormat.
-    return &number_format;
+    return number_format;
 }

 // 15.1.3 SetNumberFormatDigitOptions ( intlObj, options, mnfdDefault, mxfdDefault, notation ), https://tc39.es/ecma402/#sec-setnfdigitoptions
@ -473,7 +473,7 @@ ThrowCompletionOr<void> set_number_format_unit_options(VM& vm, NumberFormat& int
    // 14. If style is "currency", then
    if (intl_object.style() == NumberFormat::Style::Currency) {
        // a. Set intlObj.[[Currency]] to the ASCII-uppercase of currency.
-        intl_object.set_currency(TRY_OR_THROW_OOM(vm, currency.as_string().utf8_string().to_uppercase()));
+        intl_object.set_currency(MUST(currency.as_string().utf8_string().to_uppercase()));

        // c. Set intlObj.[[CurrencyDisplay]] to currencyDisplay.
        intl_object.set_currency_display(currency_display.as_string().utf8_string_view());
--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatConstructor.h
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatConstructor.h
@ -29,7 +29,7 @@ private:
    JS_DECLARE_NATIVE_FUNCTION(supported_locales_of);
 };

-ThrowCompletionOr<NumberFormat*> initialize_number_format(VM&, NumberFormat&, Value locales_value, Value options_value);
+ThrowCompletionOr<NonnullGCPtr<NumberFormat>> initialize_number_format(VM&, NumberFormat&, Value locales_value, Value options_value);
 ThrowCompletionOr<void> set_number_format_digit_options(VM&, NumberFormatBase& intl_object, Object const& options, int default_min_fraction_digits, int default_max_fraction_digits, NumberFormat::Notation notation);
 ThrowCompletionOr<void> set_number_format_unit_options(VM&, NumberFormat& intl_object, Object const& options);

--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatFunction.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatFunction.cpp
@ -44,7 +44,7 @@ ThrowCompletionOr<Value> NumberFormatFunction::call()
    auto mathematical_value = TRY(to_intl_mathematical_value(vm, value));

    // 5. Return ? FormatNumeric(nf, x).
-    auto formatted = TRY(format_numeric(vm, m_number_format, move(mathematical_value)));
+    auto formatted = format_numeric(vm, m_number_format, move(mathematical_value));
    return PrimitiveString::create(vm, move(formatted));
 }

--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatPrototype.cpp
@ -75,7 +75,7 @@ JS_DEFINE_NATIVE_FUNCTION(NumberFormatPrototype::format_to_parts)
    auto mathematical_value = TRY(to_intl_mathematical_value(vm, value));

    // 4. Return ? FormatNumericToParts(nf, x).
-    return TRY(format_numeric_to_parts(vm, number_format, move(mathematical_value)));
+    return format_numeric_to_parts(vm, number_format, move(mathematical_value));
 }

 // 15.3.5 Intl.NumberFormat.prototype.formatRange ( start, end ), https://tc39.es/ecma402/#sec-intl.numberformat.prototype.formatrange
@ -172,7 +172,7 @@ JS_DEFINE_NATIVE_FUNCTION(NumberFormatPrototype::resolved_options)
        MUST(options->create_data_property_or_throw(vm.names.minimumSignificantDigits, Value(number_format->min_significant_digits())));
    if (number_format->has_max_significant_digits())
        MUST(options->create_data_property_or_throw(vm.names.maximumSignificantDigits, Value(number_format->max_significant_digits())));
-    MUST(options->create_data_property_or_throw(vm.names.useGrouping, MUST_OR_THROW_OOM(number_format->use_grouping_to_value(vm))));
+    MUST(options->create_data_property_or_throw(vm.names.useGrouping, number_format->use_grouping_to_value(vm)));
    MUST(options->create_data_property_or_throw(vm.names.notation, PrimitiveString::create(vm, number_format->notation_string())));
    if (number_format->has_compact_display())
        MUST(options->create_data_property_or_throw(vm.names.compactDisplay, PrimitiveString::create(vm, number_format->compact_display_string())));
--- a/Userland/Libraries/LibJS/Runtime/Intl/PluralRules.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/PluralRules.cpp
@ -92,13 +92,13 @@ PluralRules::PluralRules(Object& prototype)
 }

 // 16.5.3 ResolvePlural ( pluralRules, n ), https://tc39.es/ecma402/#sec-resolveplural
-ThrowCompletionOr<ResolvedPlurality> resolve_plural(VM& vm, PluralRules const& plural_rules, Value number)
+ResolvedPlurality resolve_plural(PluralRules const& plural_rules, Value number)
 {
-    return resolve_plural(vm, plural_rules, plural_rules.type(), number);
+    return resolve_plural(plural_rules, plural_rules.type(), number);
 }

 // Non-standard overload of ResolvePlural to allow using the AO without an Intl.PluralRules object.
-ThrowCompletionOr<ResolvedPlurality> resolve_plural(VM& vm, NumberFormatBase const& number_format, ::Locale::PluralForm type, Value number)
+ResolvedPlurality resolve_plural(NumberFormatBase const& number_format, ::Locale::PluralForm type, Value number)
 {
    // 1. Assert: Type(pluralRules) is Object.
    // 2. Assert: pluralRules has an [[InitializedPluralRules]] internal slot.
@ -107,7 +107,7 @@ ThrowCompletionOr<ResolvedPlurality> resolve_plural(VM& vm, NumberFormatBase con
    // 4. If n is not a finite Number, then
    if (!number.is_finite_number()) {
        // a. Return "other".
-        return ResolvedPlurality { ::Locale::PluralCategory::Other, String {} };
+        return { ::Locale::PluralCategory::Other, String {} };
    }

    // 5. Let locale be pluralRules.[[Locale]].
@ -116,7 +116,7 @@ ThrowCompletionOr<ResolvedPlurality> resolve_plural(VM& vm, NumberFormatBase con
    // 6. Let type be pluralRules.[[Type]].

    // 7. Let res be ! FormatNumericToString(pluralRules, n).
-    auto result = MUST_OR_THROW_OOM(format_numeric_to_string(vm, number_format, number));
+    auto result = format_numeric_to_string(number_format, number);

    // 8. Let s be res.[[FormattedString]].
    auto string = move(result.formatted_string);
@ -128,7 +128,7 @@ ThrowCompletionOr<ResolvedPlurality> resolve_plural(VM& vm, NumberFormatBase con
    auto plural_category = plural_rule_select(locale, type, number, move(operands));

    // 11. Return the Record { [[PluralCategory]]: p, [[FormattedString]]: s }.
-    return ResolvedPlurality { plural_category, move(string) };
+    return { plural_category, move(string) };
 }

 // 16.5.4 PluralRuleSelectRange ( locale, type, xp, yp ), https://tc39.es/ecma402/#sec-resolveplural
@ -152,10 +152,10 @@ ThrowCompletionOr<::Locale::PluralCategory> resolve_plural_range(VM& vm, PluralR
        return vm.throw_completion<RangeError>(ErrorType::NumberIsNaN, "end"sv);

    // 6. Let xp be ! ResolvePlural(pluralRules, x).
-    auto start_plurality = MUST_OR_THROW_OOM(resolve_plural(vm, plural_rules, start));
+    auto start_plurality = resolve_plural(plural_rules, start);

    // 7. Let yp be ! ResolvePlural(pluralRules, y).
-    auto end_plurality = MUST_OR_THROW_OOM(resolve_plural(vm, plural_rules, end));
+    auto end_plurality = resolve_plural(plural_rules, end);

    // 8. If xp.[[FormattedString]] is yp.[[FormattedString]], then
    if (start_plurality.formatted_string == end_plurality.formatted_string) {
--- a/Userland/Libraries/LibJS/Runtime/Intl/PluralRules.h
+++ b/Userland/Libraries/LibJS/Runtime/Intl/PluralRules.h
@ -38,8 +38,8 @@ struct ResolvedPlurality {

 ::Locale::PluralOperands get_operands(StringView string);
 ::Locale::PluralCategory plural_rule_select(StringView locale, ::Locale::PluralForm type, Value number, ::Locale::PluralOperands operands);
-ThrowCompletionOr<ResolvedPlurality> resolve_plural(VM&, PluralRules const&, Value number);
-ThrowCompletionOr<ResolvedPlurality> resolve_plural(VM&, NumberFormatBase const& number_format, ::Locale::PluralForm type, Value number);
+ResolvedPlurality resolve_plural(PluralRules const&, Value number);
+ResolvedPlurality resolve_plural(NumberFormatBase const& number_format, ::Locale::PluralForm type, Value number);
 ::Locale::PluralCategory plural_rule_select_range(StringView locale, ::Locale::PluralForm, ::Locale::PluralCategory start, ::Locale::PluralCategory end);
 ThrowCompletionOr<::Locale::PluralCategory> resolve_plural_range(VM&, PluralRules const&, Value start, Value end);

--- a/Userland/Libraries/LibJS/Runtime/Intl/PluralRulesConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/PluralRulesConstructor.cpp
@ -54,7 +54,7 @@ ThrowCompletionOr<NonnullGCPtr<Object>> PluralRulesConstructor::construct(Functi
    auto plural_rules = TRY(ordinary_create_from_constructor<PluralRules>(vm, new_target, &Intrinsics::intl_plural_rules_prototype));

    // 3. Return ? InitializePluralRules(pluralRules, locales, options).
-    return *TRY(initialize_plural_rules(vm, plural_rules, locales, options));
+    return TRY(initialize_plural_rules(vm, plural_rules, locales, options));
 }

 // 16.2.2 Intl.PluralRules.supportedLocalesOf ( locales [ , options ] ), https://tc39.es/ecma402/#sec-intl.pluralrules.supportedlocalesof
@ -73,7 +73,7 @@ JS_DEFINE_NATIVE_FUNCTION(PluralRulesConstructor::supported_locales_of)
 }

 // 16.1.2 InitializePluralRules ( pluralRules, locales, options ), https://tc39.es/ecma402/#sec-initializepluralrules
-ThrowCompletionOr<PluralRules*> initialize_plural_rules(VM& vm, PluralRules& plural_rules, Value locales_value, Value options_value)
+ThrowCompletionOr<NonnullGCPtr<PluralRules>> initialize_plural_rules(VM& vm, PluralRules& plural_rules, Value locales_value, Value options_value)
 {
    // 1. Let requestedLocales be ? CanonicalizeLocaleList(locales).
    auto requested_locales = TRY(canonicalize_locale_list(vm, locales_value));
@ -110,7 +110,7 @@ ThrowCompletionOr<PluralRules*> initialize_plural_rules(VM& vm, PluralRules& plu
    plural_rules.set_data_locale(move(result.data_locale));

    // 12. Return pluralRules.
-    return &plural_rules;
+    return plural_rules;
 }

 }
--- a/Userland/Libraries/LibJS/Runtime/Intl/PluralRulesConstructor.h
+++ b/Userland/Libraries/LibJS/Runtime/Intl/PluralRulesConstructor.h
@ -28,6 +28,6 @@ private:
    JS_DECLARE_NATIVE_FUNCTION(supported_locales_of);
 };

-ThrowCompletionOr<PluralRules*> initialize_plural_rules(VM&, PluralRules&, Value locales_value, Value options_value);
+ThrowCompletionOr<NonnullGCPtr<PluralRules>> initialize_plural_rules(VM&, PluralRules&, Value locales_value, Value options_value);

 }
--- a/Userland/Libraries/LibJS/Runtime/Intl/PluralRulesPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/PluralRulesPrototype.cpp
@ -44,7 +44,7 @@ JS_DEFINE_NATIVE_FUNCTION(PluralRulesPrototype::select)
    auto number = TRY(vm.argument(0).to_number(vm));

    // 4. Return ! ResolvePlural(pr, n).[[PluralCategory]].
-    auto plurality = MUST_OR_THROW_OOM(resolve_plural(vm, plural_rules, number));
+    auto plurality = resolve_plural(plural_rules, number);
    return PrimitiveString::create(vm, ::Locale::plural_category_to_string(plurality.plural_category));
 }

--- a/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormat.cpp
@ -176,10 +176,10 @@ ThrowCompletionOr<Vector<PatternPartitionWithUnit>> partition_relative_time_patt
    auto patterns = find_patterns_for_tense_or_number(tense);

    // 20. Let fv be ! PartitionNumberPattern(relativeTimeFormat.[[NumberFormat]], value).
-    auto value_partitions = MUST_OR_THROW_OOM(partition_number_pattern(vm, relative_time_format.number_format(), Value(value)));
+    auto value_partitions = partition_number_pattern(vm, relative_time_format.number_format(), Value(value));

    // 21. Let pr be ! ResolvePlural(relativeTimeFormat.[[PluralRules]], value).[[PluralCategory]].
-    auto plurality = MUST_OR_THROW_OOM(resolve_plural(vm, relative_time_format.plural_rules(), Value(value)));
+    auto plurality = resolve_plural(relative_time_format.plural_rules(), Value(value));

    // 22. Let pattern be po.[[<pr>]].
    auto pattern = patterns.find_if([&](auto& p) { return p.plurality == plurality.plural_category; });
--- a/Userland/Libraries/LibJS/Runtime/NumberPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/NumberPrototype.cpp
@ -287,7 +287,7 @@ JS_DEFINE_NATIVE_FUNCTION(NumberPrototype::to_locale_string)
    auto* number_format = static_cast<Intl::NumberFormat*>(TRY(construct(vm, realm.intrinsics().intl_number_format_constructor(), locales, options)).ptr());

    // 3. Return ? FormatNumeric(numberFormat, x).
-    auto formatted = TRY(Intl::format_numeric(vm, *number_format, number_value));
+    auto formatted = Intl::format_numeric(vm, *number_format, number_value);
    return PrimitiveString::create(vm, move(formatted));
 }