diff --git a/source/generate/clean.ts b/source/generate/clean.ts
new file mode 100644
index 0000000..08d5f38
--- /dev/null
+++ b/source/generate/clean.ts
@@ -0,0 +1,15 @@
+import fs from "fs"
+
+import { contentDirectoryPath, mapFilePath } from "./config"
+
+export default function clean() {
+	try {
+		fs.rmSync(contentDirectoryPath, { recursive: true })
+		// eslint-disable-next-line no-empty
+	} catch (err) {}
+
+	try {
+		fs.unlinkSync(mapFilePath)
+		// eslint-disable-next-line no-empty
+	} catch (err) {}
+}
diff --git a/source/generate/index.ts b/source/generate/index.ts
index 52197ff..751cd93 100644
--- a/source/generate/index.ts
+++ b/source/generate/index.ts
@@ -8,9 +8,11 @@
 
 import fs from "fs"
 
-import { contentDirectoryPath, mapFilePath, markdownPath } from "./config"
+import { mapFilePath, markdownPath } from "./config"
 import { recursiveParse } from "./recursiveParse"
 import { saveIndex } from "./searchIndex"
+import postProcess from "./postProcess"
+import clean from "./clean"
 
 import { Map, ParseMode, SeriesMap, PortfolioData } from "../types/typing"
 
@@ -34,15 +36,7 @@ export const portfolioData: PortfolioData = {
  * Delete previously generated files
  */
 
-try {
-	fs.rmSync(contentDirectoryPath, { recursive: true })
-	// eslint-disable-next-line no-empty
-} catch (err) {}
-
-try {
-	fs.unlinkSync(mapFilePath)
-	// eslint-disable-next-line no-empty
-} catch (err) {}
+clean()
 
 /**
  * Checking
@@ -72,35 +66,7 @@ recursiveParse(ParseMode.SERIES, markdownPath + "/series")
  * Post-process
  */
 
-// sort date
-
-const TmpDate = map.date
-map.date = {}
-Object.keys(map.date)
-	.sort()
-	.forEach((sortedDateKey) => {
-		map.date[sortedDateKey] = TmpDate[sortedDateKey]
-	})
-
-// fill meta data
-
-map.meta.tags = Object.keys(map.tags)
-
-// sort series post
-
-for (const seriesURL in seriesMap) {
-	seriesMap[seriesURL].sort((a, b) => {
-		if (a.index < b.index) return -1
-		if (a.index > b.index) return 1
-
-		return 0
-	})
-}
-
-for (const seriesURL in seriesMap) {
-	map.series[seriesURL].length = seriesMap[seriesURL].length
-	map.series[seriesURL].order = seriesMap[seriesURL].map((item) => item.url)
-}
+postProcess()
 
 /**
  * Save results
diff --git a/source/generate/postProcess.ts b/source/generate/postProcess.ts
new file mode 100644
index 0000000..d01f1b5
--- /dev/null
+++ b/source/generate/postProcess.ts
@@ -0,0 +1,35 @@
+import { map, seriesMap } from "."
+
+export default function postProcess() {
+	// sort date
+
+	const TmpDate = map.date
+	map.date = {}
+	Object.keys(map.date)
+		.sort()
+		.forEach((sortedDateKey) => {
+			map.date[sortedDateKey] = TmpDate[sortedDateKey]
+		})
+
+	// fill meta data
+
+	map.meta.tags = Object.keys(map.tags)
+
+	// sort series post
+
+	for (const seriesURL in seriesMap) {
+		seriesMap[seriesURL].sort((a, b) => {
+			if (a.index < b.index) return -1
+			if (a.index > b.index) return 1
+
+			return 0
+		})
+	}
+
+	for (const seriesURL in seriesMap) {
+		map.series[seriesURL].length = seriesMap[seriesURL].length
+		map.series[seriesURL].order = seriesMap[seriesURL].map(
+			(item) => item.url
+		)
+	}
+}