webpack#172 - Support alternative fs implementations.

Author: dazinator

lib/NodeJsInputFileSystem.js

@@ -4,11 +4,31 @@
 */
 "use strict";
 
-const fs = require("graceful-fs");
+const defaultFs = require("graceful-fs");
+
+const fsMethods = [
+	"stat",
+	"statSync",
+	"readFile",
+	"readFileSync",
+	"readlink",
+	"readlinkSync"
+];
 
 class NodeJsInputFileSystem {
+	constructor(fs) {
+		this.fs = fs || defaultFs;
+		for (const key of fsMethods) {
+			Object.defineProperty(this, key, {
+				configurable: true,
+				writable: true,
+				value: this.fs[key].bind(this.fs)
+			});
+		}
+	}
+
 	readdir(path, callback) {
-		fs.readdir(path, (err, files) => {
+		this.fs.readdir(path, (err, files) => {
 			callback(
 				err,
 				files &&
@@ -20,7 +40,7 @@ class NodeJsInputFileSystem {
 	}
 
 	readdirSync(path) {
-		const files = fs.readdirSync(path);
+		const files = this.fs.readdirSync(path);
 		return (
 			files &&
 			files.map(file => {
@@ -30,21 +50,4 @@ class NodeJsInputFileSystem {
 	}
 }
 
-const fsMethods = [
-	"stat",
-	"statSync",
-	"readFile",
-	"readFileSync",
-	"readlink",
-	"readlinkSync"
-];
-
-for (const key of fsMethods) {
-	Object.defineProperty(NodeJsInputFileSystem.prototype, key, {
-		configurable: true,
-		writable: true,
-		value: fs[key].bind(fs)
-	});
-}
-
 module.exports = NodeJsInputFileSystem;