Fix: ES5 client (#2658)

Author: knagaitsev

client-src/default/index.js

@@ -6,7 +6,7 @@ window.process = window.process || {};
 window.process.env = window.process.env || {};
 
 /* global __resourceQuery WorkerGlobalScope self */
-const stripAnsi = require('strip-ansi');
+const stripAnsi = require('../transpiled-modules/strip-ansi');
 const socket = require('./socket');
 const overlay = require('./overlay');
 const { log, setLogLevel } = require('./utils/log');

client-src/default/utils/log.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const log = require('webpack/lib/logging/runtime');
+const log = require('../../transpiled-modules/log');
 
 const name = 'webpack-dev-server';
 // default level is set on the client side, so it does not need

client-src/transpiled-modules/log.js

@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = require('webpack/lib/logging/runtime');

client-src/transpiled-modules/strip-ansi.js

@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = require('strip-ansi');

client-src/transpiled-modules/webpack.config.js

@@ -0,0 +1,39 @@
+'use strict';
+
+const path = require('path');
+const merge = require('webpack-merge');
+
+const base = {
+  mode: 'production',
+  output: {
+    path: path.resolve(__dirname, '../../client/transpiled-modules'),
+    libraryTarget: 'commonjs2',
+  },
+  module: {
+    rules: [
+      {
+        test: /\.js$/,
+        use: [
+          {
+            loader: 'babel-loader',
+          },
+        ],
+      },
+    ],
+  },
+};
+
+module.exports = [
+  merge(base, {
+    entry: path.join(__dirname, 'log.js'),
+    output: {
+      filename: 'log.js',
+    },
+  }),
+  merge(base, {
+    entry: path.join(__dirname, 'strip-ansi.js'),
+    output: {
+      filename: 'strip-ansi.js',
+    },
+  }),
+];

package-lock.json

@@ -29,6 +29,7 @@
     "build:client:clients": "babel client-src/clients --out-dir client/clients",
     "build:client:index": "webpack --color --config client-src/default/webpack.config.js",
     "build:client:sockjs": "webpack --color --config client-src/sockjs/webpack.config.js",
+    "build:client:transpiled-modules": "webpack --color --config client-src/transpiled-modules/webpack.config.js",
     "build:client": "rimraf ./client/* && npm-run-all -s -l -p \"build:client:**\"",
     "webpack-dev-server": "node examples/run-example.js",
     "release": "standard-version"
@@ -74,6 +75,7 @@
     "@commitlint/cli": "^9.1.2",
     "@commitlint/config-conventional": "^10.0.0",
     "@jest/test-sequencer": "^26.3.0",
+    "acorn": "^8.0.1",
     "babel-jest": "^26.3.0",
     "babel-loader": "^8.1.0",
     "body-parser": "^1.19.0",
@@ -107,7 +109,8 @@
     "typescript": "^3.9.7",
     "url-loader": "^4.1.0",
     "webpack": "^4.44.1",
-    "webpack-cli": "^3.3.12"
+    "webpack-cli": "^3.3.12",
+    "webpack-merge": "^4.2.2"
   },
   "peerDependencies": {
     "webpack": "^4.0.0 || ^5.0.0"

package.json

@@ -0,0 +1,79 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const acorn = require('acorn');
+const request = require('supertest');
+const testServer = require('../helpers/test-server');
+const config = require('../fixtures/simple-config/webpack.config');
+const port = require('../ports-map').bundle;
+const isWebpack5 = require('../helpers/isWebpack5');
+
+describe('bundle', () => {
+  // the ES5 check test for the bundle will not work on webpack@5,
+  // because webpack@5 bundle output uses some ES6 syntax that can
+  // only be avoided with babel-loader
+  const runBundleTest = isWebpack5 ? describe.skip : describe;
+
+  runBundleTest('index.bundle.js bundled output', () => {
+    it('should parse with ES5', () => {
+      const bundleStr = fs.readFileSync(
+        path.resolve(__dirname, '../../client/default/index.bundle.js'),
+        'utf8'
+      );
+      expect(() => {
+        acorn.parse(bundleStr, {
+          ecmaVersion: 5,
+        });
+      }).not.toThrow();
+    });
+  });
+
+  runBundleTest('main.js bundled output', () => {
+    let server;
+    let req;
+
+    beforeAll((done) => {
+      server = testServer.start(config, { port }, done);
+      req = request(server.app);
+    });
+
+    afterAll(testServer.close);
+
+    it('should get full user bundle and parse with ES5', async () => {
+      const { text } = await req
+        .get('/main.js')
+        .expect('Content-Type', 'application/javascript; charset=utf-8')
+        .expect(200);
+
+      expect(() => {
+        let evalStep = 0;
+        acorn.parse(text, {
+          ecmaVersion: 5,
+          onToken: (token) => {
+            // a webpack bundle is a series of evaluated JavaScript
+            // strings like this: eval('...')
+            // if we want the bundle to work using ES5, we need to
+            // check that these strings are good with ES5 as well
+
+            // this can be done by waiting for tokens during the main parse
+            // then when we hit a string in an 'eval' function we also try
+            // to parse that string with ES5
+            if (token.type.label === 'name' && token.value === 'eval') {
+              evalStep += 1;
+            } else if (token.type.label === '(' && evalStep === 1) {
+              evalStep += 1;
+            } else if (token.type.label === 'string' && evalStep === 2) {
+              const program = token.value;
+              acorn.parse(program, {
+                ecmaVersion: 5,
+              });
+
+              evalStep = 0;
+            }
+          },
+        });
+      }).not.toThrow();
+    });
+  });
+});

test/client/bundle.test.js

@@ -42,6 +42,8 @@ const portsList = {
   Iframe: 1,
   SocketInjection: 1,
   'static-publicPath-option': 1,
+  'contentBasePublicPath-option': 1,
+  bundle: 1,
 };
 
 let startPort = 8089;