Merge pull request webpack#5194 from webpack/feature/hoist_regex_literals

sokra · web-flow · commit 7e757cd13bbc · 2017-07-06T23:46:01.000+02:00
feat(perf): Hoist RegExp literals in RequestShortener
diff --git a/lib/RequestShortener.js b/lib/RequestShortener.js
@@ -5,39 +5,48 @@
 "use strict";
 
 const path = require("path");
+const NORMALIZE_SLASH_DIRECTION_REGEXP = /\\/g;
+const PATH_CHARS_REGEXP = /[-[\]{}()*+?.,\\^$|#\s]/g;
+const SEPARATOR_REGEXP = /[/\\]$/;
+const FRONT_OR_BACK_BANG_REGEXP = /^!|!$/g;
+const INDEX_JS_REGEXP = /\/index.js(!|\?|\(query\))/g;
+
+const normalizeBackSlashDirection = (request) => {
+	return request.replace(NORMALIZE_SLASH_DIRECTION_REGEXP, "/");
+};
+
+const createRegExpForPath = (path) => {
+	const regexpTypePartial = path.replace(PATH_CHARS_REGEXP, "\\$&");
+	return new RegExp(`(^|!)${regexpTypePartial}`, "g");
+};
 
 class RequestShortener {
 	constructor(directory) {
-		directory = directory.replace(/\\/g, "/");
-		if(/[\/\\]$/.test(directory)) directory = directory.substr(0, directory.length - 1);
+		directory = normalizeBackSlashDirection(directory);
+		if(SEPARATOR_REGEXP.test(directory)) directory = directory.substr(0, directory.length - 1);
 
 		if(directory) {
-			const currentDirectoryRegExpString = directory.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
-			this.currentDirectoryRegExp = new RegExp("^" + currentDirectoryRegExpString + "|(!)" + currentDirectoryRegExpString, "g");
+			this.currentDirectoryRegExp = createRegExpForPath(directory);
 		}
 
 		const dirname = path.dirname(directory);
-		const endsWithSeperator = /[\/\\]$/.test(dirname);
+		const endsWithSeperator = SEPARATOR_REGEXP.test(dirname);
 		const parentDirectory = endsWithSeperator ? dirname.substr(0, dirname.length - 1) : dirname;
 		if(parentDirectory && parentDirectory !== directory) {
-			const parentDirectoryRegExpString = parentDirectory.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
-			this.parentDirectoryRegExp = new RegExp("^" + parentDirectoryRegExpString + "|(!)" + parentDirectoryRegExpString, "g");
+			this.parentDirectoryRegExp = createRegExpForPath(parentDirectory);
 		}
 
 		if(__dirname.length >= 2) {
-			const buildins = path.join(__dirname, "..").replace(/\\/g, "/");
+			const buildins = normalizeBackSlashDirection(path.join(__dirname, ".."));
 			const buildinsAsModule = this.currentDirectoryRegExp && this.currentDirectoryRegExp.test(buildins);
 			this.buildinsAsModule = buildinsAsModule;
-			const buildinsRegExpString = buildins.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
-			this.buildinsRegExp = new RegExp("^" + buildinsRegExpString + "|(!)" + buildinsRegExpString, "g");
+			this.buildinsRegExp = createRegExpForPath(buildins);
 		}
-
-		this.indexJsRegExp = /\/index.js(!|\?|\(query\))/g;
 	}
 
 	shorten(request) {
 		if(!request) return request;
-		request = request.replace(/\\/g, "/");
+		request = normalizeBackSlashDirection(request);
 		if(this.buildinsAsModule && this.buildinsRegExp)
 			request = request.replace(this.buildinsRegExp, "!(webpack)");
 		if(this.currentDirectoryRegExp)
@@ -46,8 +55,8 @@ class RequestShortener {
 			request = request.replace(this.parentDirectoryRegExp, "!..");
 		if(!this.buildinsAsModule && this.buildinsRegExp)
 			request = request.replace(this.buildinsRegExp, "!(webpack)");
-		request = request.replace(this.indexJsRegExp, "$1");
-		return request.replace(/^!|!$/, "");
+		request = request.replace(INDEX_JS_REGEXP, "$1");
+		return request.replace(FRONT_OR_BACK_BANG_REGEXP, "");
 	}
 }
 
