Merge pull request #2 from privatenumber/develop

.github/workflows/release.yml

@@ -26,6 +26,6 @@ jobs:
       run: npm run test --if-present
     - name: Release
       env:
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        GH_TOKEN: ${{ secrets.GH_TOKEN }}
         NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
       run: npx semantic-release

README.md

@@ -39,5 +39,31 @@ const helloWorld = fsRequire('/hello-world')
 console.log(helloWorld()) // Hello world!
 ```
 
+## ⚙️ API
+
+### createFsRequire(fs, options?)
+Returns a `require(modulePath)` function that resolves from the file-system passed in.
+
+#### fs
+Type: `FileSystem`
+
+Required
+
+The file-system to resolve requires from.
+
+#### options
+##### options.fs
+
+Type: `boolean | FileSystem`
+
+Code executed the virtual file-system may `require('fs')` and this may either pose as a security concern or yield inconsistent results as the virtual file won't not accessible through the actual `fs` module.
+
+By default `require('fs')` is shimmed to the file-system passed into `createFsRequire`.
+
+To disable this behavior and resolve to the real `fs` module, set this to `true`.
+
+You can also pass in a different file-system too.
+
+
 ## 👨‍👩‍👧 Related
 - [fs-monkey](https://github.com/streamich/fs-monkey) - By the same author of [memfs](https://github.com/streamich/memfs). Patches the global `require` to access a virtual fs.

src/fs-require.ts

@@ -72,7 +72,14 @@ const realRequire = require;
 
 let idCounter = 0;
 
-export const createFsRequire = (mfs: FileSystem) => {
+type Options = {
+	fs?: boolean | FileSystem;
+};
+
+export const createFsRequire = (
+	mfs: FileSystem,
+	options?: Options,
+) => {
 	idCounter += 1;
 	const fsRequireId = idCounter;
 	const moduleCache = new Map<string, Module>();
@@ -81,11 +88,19 @@ export const createFsRequire = (mfs: FileSystem) => {
 		const require = (modulePath: string) => {
 			if (!isFilePathPattern.test(modulePath)) {
 				const [moduleName, moduleSubpath] = getBareSpecifier(modulePath) ?? [];
+
 				if (moduleName === 'fs') {
-					if (moduleSubpath) {
-						throw new Error(`Cannot find module '${modulePath}'`);
+					const { fs } = options ?? {};
+					if (!fs) {
+						if (moduleSubpath) {
+							throw new Error(`Cannot find module '${modulePath}'`);
+						}
+						return mfs;
+					}
+
+					if (fs !== true) {
+						return fs;
 					}
-					return mfs;
 				}
 
 				return realRequire(modulePath);

tests/fs-require.spec.ts

@@ -117,29 +117,66 @@ test('native module', () => {
 	expect(fsRequire('/index')).toBe(path);
 });
 
-test('mock fs', () => {
-	const randomNumber = Math.random().toString();
-	const vol = Volume.fromJSON({
-		'/index.js': `
-			const fs = require('fs');
-			fs.writeFileSync('/test-write', '${randomNumber}');
-		`,
+describe('mock fs', () => {
+	test('mock fs', () => {
+		const randomNumber = Math.random().toString();
+		const vol = Volume.fromJSON({
+			'/index.js': `
+				const fs = require('fs');
+				fs.writeFileSync('/test-write', '${randomNumber}');
+			`,
+		});
+		const fsRequire = createFsRequire(vol);
+
+		fsRequire('/index');
+		expect(vol.readFileSync('/test-write').toString()).toBe(randomNumber);
 	});
-	const fsRequire = createFsRequire(vol);
 
-	fsRequire('/index');
-	expect(vol.readFileSync('/test-write').toString()).toBe(randomNumber);
-});
+	test('mock fs - fs/promises fails', () => {
+		const vol = Volume.fromJSON({
+			'/index.js': `
+				const fs = require('fs/promises');
+			`,
+		});
+		const fsRequire = createFsRequire(vol);
 
-test('mock fs - fs/promises fails', () => {
-	const vol = Volume.fromJSON({
-		'/index.js': `
-			const fs = require('fs/promises');
-		`,
+		expect(() => fsRequire('/index')).toThrow('Cannot find module \'fs/promises\'');
 	});
-	const fsRequire = createFsRequire(vol);
 
-	expect(() => fsRequire('/index')).toThrow('Cannot find module \'fs/promises\'');
+	test('disabled', () => {
+		const vol = Volume.fromJSON({
+			'/index.js': `
+				const fs = require('fs');
+				module.exports = fs.readdirSync('${__dirname}');
+			`,
+		});
+
+		const fsRequire = createFsRequire(vol, {
+			fs: true,
+		});
+
+		const files = fsRequire('/index');
+		expect(files.includes('fs-require.spec.ts')).toBe(true);
+	});
+
+	test('custom', () => {
+		const randomNumber = Math.random().toString();
+		const customFs = Volume.fromJSON({
+			'/some-file': randomNumber,
+		});
+		const vol = Volume.fromJSON({
+			'/index.js': `
+				const fs = require('fs');
+				module.exports = fs.readFileSync('/some-file').toString();
+			`,
+		});
+
+		const fsRequire = createFsRequire(vol, {
+			fs: customFs,
+		});
+
+		expect(fsRequire('/index')).toBe(randomNumber);
+	});
 });
 
 test('Works with real fs', () => {