replace browserify with rollup and babel (#4293)

* Make browser specific TTY interop explicit instead of a magic bundling configuration
* Remove unnessessary browserify ignore of cli related files and chokidar
* Extract lookupFiles from utils to avoid node dependencies in browser bundle
* Replace browserify with rollup for main library bundling
* Polyfill global to check if IE11 will start working
* Don't include esm-utils in browser build. Modern syntax breaks IE
* Remove duplicate browserify configuration in karma config file
* Add custom karma rollup plugin and use it to bundle browser tests
* add process.listeners impl
* Extract browser-only helper functions from shared utils file to their own files
* Add browserslist, babel, babel-preset-env and prepare for modern js
* Add mocha.js.map to npm distributed files
* Use util function to check if we're running in a browser
* Improve documentation of self-built karma-rollup-plugin
* Renamed lib/cli/lookupFiles.js to lib/cli/lookup-files.js
* Clean up rollup config
* Kebab case file names
* Remove last traces of unused browserify
* fix bundle path under win32
* do not run bundle visualizer in CI
* Remove use of mocha.opts in browser testing
* Improved naming of rollup plugin to pick values from package.json

Co-authored-by: Christopher Hiller <boneskull@boneskull.com>
Signed-off-by: Christopher Hiller <boneskull@boneskull.com>

.browserslistrc

@@ -0,0 +1,12 @@
+node >= 10
+last 2 Chrome versions
+last 2 Edge versions
+last 2 Firefox versions
+last 2 Safari versions
+last 2 Opera versions
+unreleased Chrome versions
+unreleased Edge versions
+unreleased Firefox versions
+unreleased Safari versions
+unreleased Opera versions
+IE 11

.eslintrc.yml

@@ -5,8 +5,9 @@ extends:
 env:
   node: true
   browser: true
+  es6: true
 parserOptions:
-  ecmaVersion: 5
+  ecmaVersion: 2018
   ecmaFeatures:
     jsx: false
   sourceType: script
@@ -37,8 +38,6 @@ overrides:
       - 'test/integration/helpers.js'
       - 'test/integration/options/watch.spec.js'
       - 'test/node-unit/**/*.js'
-    parserOptions:
-      ecmaVersion: 2018
     env:
       browser: false
     rules:
@@ -48,6 +47,8 @@ overrides:
           property: 'assign'
   - files:
       - esm-utils.js
+      - rollup.config.js
+      - scripts/pick-from-package-json.js
     parserOptions:
       ecmaVersion: 2018
       sourceType: module

.gitignore

@@ -3,9 +3,13 @@ docs/_site
 docs/_dist
 docs/images/supporters
 mocha.js
+mocha.js.map
 .karma/
 !lib/mocha.js
 
+# Bundle debugging
+stats.html
+
 #########################################
 # NON-MOCHA STUFF GOES BELOW THIS THING #
 #########################################

browser-entry.js

@@ -9,6 +9,8 @@
 
 process.stdout = require('browser-stdout')({label: false});
 
+var parseQuery = require('./lib/browser/parse-query');
+var highlightTags = require('./lib/browser/highlight-tags');
 var Mocha = require('./lib/mocha');
 
 /**
@@ -77,6 +79,13 @@ process.on = function(e, fn) {
   }
 };
 
+process.listeners = function(e) {
+  if (e === 'uncaughtException') {
+    return uncaughtExceptionHandlers;
+  }
+  return [];
+};
+
 // The BDD UI is registered by default, but no UI will be functional in the
 // browser without an explicit call to the overridden `mocha.ui` (see below).
 // Ensure that this default UI does not expose its methods to the global scope.
@@ -163,7 +172,7 @@ mocha.run = function(fn) {
   var options = mocha.options;
   mocha.globals('location');
 
-  var query = Mocha.utils.parseQuery(global.location.search || '');
+  var query = parseQuery(global.location.search || '');
   if (query.grep) {
     mocha.grep(query.grep);
   }
@@ -182,7 +191,7 @@ mocha.run = function(fn) {
       document.getElementById('mocha') &&
       options.noHighlighting !== true
     ) {
-      Mocha.utils.highlightTags('code');
+      highlightTags('code');
     }
     if (fn) {
       fn(err);

karma.conf.js

@@ -3,6 +3,7 @@
 const fs = require('fs');
 const path = require('path');
 const os = require('os');
+const rollupPlugin = require('./scripts/karma-rollup-plugin');
 const baseBundleDirpath = path.join(__dirname, '.karma');
 
 const hostname = os.hostname();
@@ -18,51 +19,31 @@ const browserPlatformPairs = {
 module.exports = config => {
   let bundleDirpath;
   const cfg = {
-    frameworks: ['browserify', 'mocha'],
+    frameworks: ['rollup', 'mocha'],
     files: [
       // we use the BDD interface for all of the tests that
       // aren't interface-specific.
       'test/unit/*.spec.js'
     ],
-    preprocessors: {
-      'test/**/*.js': ['browserify']
-    },
-    browserify: {
-      debug: true,
-      configure: function configure(b) {
-        b.ignore('chokidar')
-          .ignore('fs')
-          .ignore('glob')
-          .ignore('path')
-          .ignore('supports-color')
-          .ignore('./lib/esm-utils.js')
-          .ignore('./lib/cli/*.js')
-          .ignore('./lib/nodejs/serializer.js')
-          .ignore('./lib/nodejs/worker.js')
-          .ignore('./lib/nodejs/buffered-worker-pool.js')
-          .ignore('./lib/nodejs/parallel-buffered-runner.js')
-          .ignore('./lib/nodejs/reporters/parallel-buffered.js')
-          .on('bundled', (err, content) => {
-            if (err) {
-              throw err;
-            }
-            if (bundleDirpath) {
-              // write bundle to directory for debugging
-              fs.writeFileSync(
-                path.join(bundleDirpath, `mocha.${Date.now()}.js`),
-                content
-              );
-            }
-          });
-      }
+    plugins: [
+      'karma-mocha',
+      'karma-mocha-reporter',
+      'karma-sauce-launcher',
+      'karma-chrome-launcher',
+      rollupPlugin
+    ],
+    rollup: {
+      configFile: 'rollup.config.js',
+      include: ['test/**'],
+      bundlePath: bundleDirpath
     },
     reporters: ['mocha'],
     colors: true,
     browsers: ['ChromeHeadless'],
     logLevel: config.LOG_INFO,
     client: {
       mocha: {
-        opts: require.resolve('./test/browser-specific/mocha.opts')
+        reporter: 'html'
       }
     },
     mochaReporter: {

lib/browser/highlight-tags.js

@@ -0,0 +1,39 @@
+'use strict';
+
+/**
+ * Highlight the given string of `js`.
+ *
+ * @private
+ * @param {string} js
+ * @return {string}
+ */
+function highlight(js) {
+  return js
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    .replace(/\/\/(.*)/gm, '<span class="comment">//$1</span>')
+    .replace(/('.*?')/gm, '<span class="string">$1</span>')
+    .replace(/(\d+\.\d+)/gm, '<span class="number">$1</span>')
+    .replace(/(\d+)/gm, '<span class="number">$1</span>')
+    .replace(
+      /\bnew[ \t]+(\w+)/gm,
+      '<span class="keyword">new</span> <span class="init">$1</span>'
+    )
+    .replace(
+      /\b(function|new|throw|return|var|if|else)\b/gm,
+      '<span class="keyword">$1</span>'
+    );
+}
+
+/**
+ * Highlight the contents of tag `name`.
+ *
+ * @private
+ * @param {string} name
+ */
+module.exports = function highlightTags(name) {
+  var code = document.getElementById('mocha').getElementsByTagName(name);
+  for (var i = 0, len = code.length; i < len; ++i) {
+    code[i].innerHTML = highlight(code[i].innerHTML);
+  }
+};

lib/browser/parse-query.js

@@ -0,0 +1,24 @@
+'use strict';
+
+/**
+ * Parse the given `qs`.
+ *
+ * @private
+ * @param {string} qs
+ * @return {Object<string, string>}
+ */
+module.exports = function parseQuery(qs) {
+  return qs
+    .replace('?', '')
+    .split('&')
+    .reduce(function(obj, pair) {
+      var i = pair.indexOf('=');
+      var key = pair.slice(0, i);
+      var val = pair.slice(++i);
+
+      // Due to how the URLSearchParams API treats spaces
+      obj[key] = decodeURIComponent(val.replace(/\+/g, '%20'));
+
+      return obj;
+    }, {});
+};

lib/cli/collect-files.js

@@ -4,8 +4,8 @@ const path = require('path');
 const ansi = require('ansi-colors');
 const debug = require('debug')('mocha:cli:run:helpers');
 const minimatch = require('minimatch');
-const utils = require('../utils');
 const {NO_FILES_MATCH_PATTERN} = require('../errors').constants;
+const lookupFiles = require('./lookup-files');
 
 /**
  * Exports a function that collects test files from CLI parameters.
@@ -27,7 +27,7 @@ module.exports = ({ignore, extension, file, recursive, sort, spec} = {}) => {
   spec.forEach(arg => {
     let newFiles;
     try {
-      newFiles = utils.lookupFiles(arg, extension, recursive);
+      newFiles = lookupFiles(arg, extension, recursive);
     } catch (err) {
       if (err.code === NO_FILES_MATCH_PATTERN) {
         unmatched.push({message: err.message, pattern: err.pattern});