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node_modules/mocha/lib/cli/watch-run.js

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+'use strict';
+
+const logSymbols = require('log-symbols');
+const debug = require('debug')('mocha:cli:watch');
+const path = require('path');
+const chokidar = require('chokidar');
+const Context = require('../context');
+const collectFiles = require('./collect-files');
+
+/**
+ * Exports the `watchRun` function that runs mocha in "watch" mode.
+ * @see module:lib/cli/run-helpers
+ * @module
+ * @private
+ */
+
+/**
+ * Run Mocha in parallel "watch" mode
+ * @param {Mocha} mocha - Mocha instance
+ * @param {Object} opts - Options
+ * @param {string[]} [opts.watchFiles] - List of paths and patterns to
+ *   watch. If not provided all files with an extension included in
+ *   `fileCollectionParams.extension` are watched. See first argument of
+ *   `chokidar.watch`.
+ * @param {string[]} opts.watchIgnore - List of paths and patterns to
+ *   exclude from watching. See `ignored` option of `chokidar`.
+ * @param {FileCollectionOptions} fileCollectParams - Parameters that control test
+ * @private
+ */
+exports.watchParallelRun = (
+  mocha,
+  {watchFiles, watchIgnore},
+  fileCollectParams
+) => {
+  debug('creating parallel watcher');
+
+  return createWatcher(mocha, {
+    watchFiles,
+    watchIgnore,
+    beforeRun({mocha}) {
+      // I don't know why we're cloning the root suite.
+      const rootSuite = mocha.suite.clone();
+
+      // ensure we aren't leaking event listeners
+      mocha.dispose();
+
+      // this `require` is needed because the require cache has been cleared.  the dynamic
+      // exports set via the below call to `mocha.ui()` won't work properly if a
+      // test depends on this module (see `required-tokens.spec.js`).
+      const Mocha = require('../mocha');
+
+      // ... and now that we've gotten a new module, we need to use it again due
+      // to `mocha.ui()` call
+      const newMocha = new Mocha(mocha.options);
+      // don't know why this is needed
+      newMocha.suite = rootSuite;
+      // nor this
+      newMocha.suite.ctx = new Context();
+
+      // reset the list of files
+      newMocha.files = collectFiles(fileCollectParams);
+
+      // because we've swapped out the root suite (see the `run` inner function
+      // in `createRerunner`), we need to call `mocha.ui()` again to set up the context/globals.
+      newMocha.ui(newMocha.options.ui);
+
+      // we need to call `newMocha.rootHooks` to set up rootHooks for the new
+      // suite
+      newMocha.rootHooks(newMocha.options.rootHooks);
+
+      // in parallel mode, the main Mocha process doesn't actually load the
+      // files. this flag prevents `mocha.run()` from autoloading.
+      newMocha.lazyLoadFiles(true);
+      return newMocha;
+    },
+    fileCollectParams
+  });
+};
+
+/**
+ * Run Mocha in "watch" mode
+ * @param {Mocha} mocha - Mocha instance
+ * @param {Object} opts - Options
+ * @param {string[]} [opts.watchFiles] - List of paths and patterns to
+ *   watch. If not provided all files with an extension included in
+ *   `fileCollectionParams.extension` are watched. See first argument of
+ *   `chokidar.watch`.
+ * @param {string[]} opts.watchIgnore - List of paths and patterns to
+ *   exclude from watching. See `ignored` option of `chokidar`.
+ * @param {FileCollectionOptions} fileCollectParams - Parameters that control test
+ *   file collection. See `lib/cli/collect-files.js`.
+ * @private
+ */
+exports.watchRun = (mocha, {watchFiles, watchIgnore}, fileCollectParams) => {
+  debug('creating serial watcher');
+
+  return createWatcher(mocha, {
+    watchFiles,
+    watchIgnore,
+    beforeRun({mocha}) {
+      mocha.unloadFiles();
+
+      // I don't know why we're cloning the root suite.
+      const rootSuite = mocha.suite.clone();
+
+      // ensure we aren't leaking event listeners
+      mocha.dispose();
+
+      // this `require` is needed because the require cache has been cleared.  the dynamic
+      // exports set via the below call to `mocha.ui()` won't work properly if a
+      // test depends on this module (see `required-tokens.spec.js`).
+      const Mocha = require('../mocha');
+
+      // ... and now that we've gotten a new module, we need to use it again due
+      // to `mocha.ui()` call
+      const newMocha = new Mocha(mocha.options);
+      // don't know why this is needed
+      newMocha.suite = rootSuite;
+      // nor this
+      newMocha.suite.ctx = new Context();
+
+      // reset the list of files
+      newMocha.files = collectFiles(fileCollectParams);
+
+      // because we've swapped out the root suite (see the `run` inner function
+      // in `createRerunner`), we need to call `mocha.ui()` again to set up the context/globals.
+      newMocha.ui(newMocha.options.ui);
+
+      // we need to call `newMocha.rootHooks` to set up rootHooks for the new
+      // suite
+      newMocha.rootHooks(newMocha.options.rootHooks);
+
+      return newMocha;
+    },
+    fileCollectParams
+  });
+};
+
+/**
+ * Bootstraps a chokidar watcher. Handles keyboard input & signals
+ * @param {Mocha} mocha - Mocha instance
+ * @param {Object} opts
+ * @param {BeforeWatchRun} [opts.beforeRun] - Function to call before
+ * `mocha.run()`
+ * @param {string[]} [opts.watchFiles] - List of paths and patterns to watch. If
+ *   not provided all files with an extension included in
+ *   `fileCollectionParams.extension` are watched. See first argument of
+ *   `chokidar.watch`.
+ * @param {string[]} [opts.watchIgnore] - List of paths and patterns to exclude
+ *   from watching. See `ignored` option of `chokidar`.
+ * @param {FileCollectionOptions} opts.fileCollectParams - List of extensions to watch if `opts.watchFiles` is not given.
+ * @returns {FSWatcher}
+ * @ignore
+ * @private
+ */
+const createWatcher = (
+  mocha,
+  {watchFiles, watchIgnore, beforeRun, fileCollectParams}
+) => {
+  if (!watchFiles) {
+    watchFiles = fileCollectParams.extension.map(ext => `**/*.${ext}`);
+  }
+
+  debug('ignoring files matching: %s', watchIgnore);
+  let globalFixtureContext;
+
+  // we handle global fixtures manually
+  mocha.enableGlobalSetup(false).enableGlobalTeardown(false);
+
+  const watcher = chokidar.watch(watchFiles, {
+    ignored: watchIgnore,
+    ignoreInitial: true
+  });
+
+  const rerunner = createRerunner(mocha, watcher, {
+    beforeRun
+  });
+
+  watcher.on('ready', async () => {
+    if (!globalFixtureContext) {
+      debug('triggering global setup');
+      globalFixtureContext = await mocha.runGlobalSetup();
+    }
+    rerunner.run();
+  });
+
+  watcher.on('all', () => {
+    rerunner.scheduleRun();
+  });
+
+  hideCursor();
+  process.on('exit', () => {
+    showCursor();
+  });
+
+  // this is for testing.
+  // win32 cannot gracefully shutdown via a signal from a parent
+  // process; a `SIGINT` from a parent will cause the process
+  // to immediately exit.  during normal course of operation, a user
+  // will type Ctrl-C and the listener will be invoked, but this
+  // is not possible in automated testing.
+  // there may be another way to solve this, but it too will be a hack.
+  // for our watch tests on win32 we must _fork_ mocha with an IPC channel
+  if (process.connected) {
+    process.on('message', msg => {
+      if (msg === 'SIGINT') {
+        process.emit('SIGINT');
+      }
+    });
+  }
+
+  let exiting = false;
+  process.on('SIGINT', async () => {
+    showCursor();
+    console.error(`${logSymbols.warning} [mocha] cleaning up, please wait...`);
+    if (!exiting) {
+      exiting = true;
+      if (mocha.hasGlobalTeardownFixtures()) {
+        debug('running global teardown');
+        try {
+          await mocha.runGlobalTeardown(globalFixtureContext);
+        } catch (err) {
+          console.error(err);
+        }
+      }
+      process.exit(130);
+    }
+  });
+
+  // Keyboard shortcut for restarting when "rs\n" is typed (ala Nodemon)
+  process.stdin.resume();
+  process.stdin.setEncoding('utf8');
+  process.stdin.on('data', data => {
+    const str = data
+      .toString()
+      .trim()
+      .toLowerCase();
+    if (str === 'rs') rerunner.scheduleRun();
+  });
+
+  return watcher;
+};
+
+/**
+ * Create an object that allows you to rerun tests on the mocha instance.
+ *
+ * @param {Mocha} mocha - Mocha instance
+ * @param {FSWatcher} watcher - chokidar `FSWatcher` instance
+ * @param {Object} [opts] - Options!
+ * @param {BeforeWatchRun} [opts.beforeRun] - Function to call before `mocha.run()`
+ * @returns {Rerunner}
+ * @ignore
+ * @private
+ */
+const createRerunner = (mocha, watcher, {beforeRun} = {}) => {
+  // Set to a `Runner` when mocha is running. Set to `null` when mocha is not
+  // running.
+  let runner = null;
+
+  // true if a file has changed during a test run
+  let rerunScheduled = false;
+
+  const run = () => {
+    try {
+      mocha = beforeRun ? beforeRun({mocha, watcher}) || mocha : mocha;
+      runner = mocha.run(() => {
+        debug('finished watch run');
+        runner = null;
+        blastCache(watcher);
+        if (rerunScheduled) {
+          rerun();
+        } else {
+          console.error(`${logSymbols.info} [mocha] waiting for changes...`);
+        }
+      });
+    } catch (e) {
+      console.error(e.stack);
+    }
+  };
+
+  const scheduleRun = () => {
+    if (rerunScheduled) {
+      return;
+    }
+
+    rerunScheduled = true;
+    if (runner) {
+      runner.abort();
+    } else {
+      rerun();
+    }
+  };
+
+  const rerun = () => {
+    rerunScheduled = false;
+    eraseLine();
+    run();
+  };
+
+  return {
+    scheduleRun,
+    run
+  };
+};
+
+/**
+ * Return the list of absolute paths watched by a chokidar watcher.
+ *
+ * @param watcher - Instance of a chokidar watcher
+ * @return {string[]} - List of absolute paths
+ * @ignore
+ * @private
+ */
+const getWatchedFiles = watcher => {
+  const watchedDirs = watcher.getWatched();
+  return Object.keys(watchedDirs).reduce(
+    (acc, dir) => [
+      ...acc,
+      ...watchedDirs[dir].map(file => path.join(dir, file))
+    ],
+    []
+  );
+};
+
+/**
+ * Hide the cursor.
+ * @ignore
+ * @private
+ */
+const hideCursor = () => {
+  process.stdout.write('\u001b[?25l');
+};
+
+/**
+ * Show the cursor.
+ * @ignore
+ * @private
+ */
+const showCursor = () => {
+  process.stdout.write('\u001b[?25h');
+};
+
+/**
+ * Erases the line on stdout
+ * @private
+ */
+const eraseLine = () => {
+  process.stdout.write('\u001b[2K');
+};
+
+/**
+ * Blast all of the watched files out of `require.cache`
+ * @param {FSWatcher} watcher - chokidar FSWatcher
+ * @ignore
+ * @private
+ */
+const blastCache = watcher => {
+  const files = getWatchedFiles(watcher);
+  files.forEach(file => {
+    delete require.cache[file];
+  });
+  debug('deleted %d file(s) from the require cache', files.length);
+};
+
+/**
+ * Callback to be run before `mocha.run()` is called.
+ * Optionally, it can return a new `Mocha` instance.
+ * @callback BeforeWatchRun
+ * @private
+ * @param {{mocha: Mocha, watcher: FSWatcher}} options
+ * @returns {Mocha}
+ */
+
+/**
+ * Object containing run control methods
+ * @typedef {Object} Rerunner
+ * @private
+ * @property {Function} run - Calls `mocha.run()`
+ * @property {Function} scheduleRun - Schedules another call to `run`
+ */