build(gulp): use chokidar alone instead of gulp-watch

Closes #1759

gulpfile.js

@@ -16,7 +16,7 @@ var merge = require('merge');
 var merge2 = require('merge2');
 var path = require('path');
 var semver = require('semver');
-var watch = require('gulp-watch');
+var watch = require('./tools/build/watch');
 
 var clean = require('./tools/build/clean');
 var transpile = require('./tools/build/transpile');
@@ -222,9 +222,7 @@ gulp.task('build/checkCircularDependencies', function (done) {
 // ------------------
 // web servers
 gulp.task('serve.js.dev', ['build.js.dev'], function(neverDone) {
-  watch('modules/**', function() {
-    gulp.start('!broccoli.js.dev');
-  });
+  watch('modules/**', '!broccoli.js.dev');
 
   jsserve(gulp, gulpPlugins, {
     path: CONFIG.dest.js.dev.es5,
@@ -304,7 +302,7 @@ function createDocsTasks(publicBuild) {
 
   gulp.task(taskPrefix, [taskPrefix + '/assets', taskPrefix + '/app', taskPrefix + '/dgeni']);
   gulp.task(taskPrefix + '/watch', function() {
-    return watch('docs/app/**/*', [taskPrefix + '/app']);
+    return watch('docs/app/**/*', { ignoreInitial: false }, [taskPrefix + '/app']);
   });
 
   gulp.task(taskPrefix + '/test', function (done) {
@@ -372,20 +370,17 @@ gulp.task('test.unit.js', ['build.js.dev'], function (neverDone) {
     'check-format'
   );
 
-  watch('modules/**', function() {
-    runSequence(
-      '!broccoli.js.dev',
-      '!test.unit.js/karma-run'
-    );
-  });
+  watch('modules/**', [
+    '!broccoli.js.dev',
+    '!test.unit.js/karma-run'
+  ]);
 });
 
 gulp.task('watch.js.dev', ['build.js.dev'], function (neverDone) {
-  watch('modules/**', function() {
-    runSequence(
-      '!broccoli.js.dev'
-    );
-  });
+  watch('modules/**', [
+    '!broccoli.js.dev',
+    '!test.unit.js/karma-run',
+  ]);
 });
 
 
@@ -404,19 +399,16 @@ gulp.task('!test.unit.js/karma-run', function(done) {
 
 
 gulp.task('test.unit.dart', ['build/tree.dart'], function (done) {
-
   runSequence(
     '!test.unit.dart/karma-server',
     '!test.unit.dart/karma-run'
   );
 
-  watch('modules/angular2/**', function() {
-    runSequence(
-      '!build/tree.dart',
-      'build/format.dart',
-      '!test.unit.dart/karma-run'
-    );
-  });
+  watch('modules/angular2/**', [
+    '!build/tree.dart',
+    'build/format.dart',
+    '!test.unit.dart/karma-run'
+  ]);
 });
 
 gulp.task('!test.unit.dart/karma-run', function (done) {
@@ -454,37 +446,29 @@ gulp.task('test.unit.cjs/ci', function(done) {
 
 
 gulp.task('test.unit.cjs', ['build/clean.js', 'build.tools'], function (done) {
-  function buildAndTest() {
-    runSequence(
-      '!build.js.cjs',
-      'test.unit.cjs/ci'
-    );
-  }
+  var buildAndTest = [
+    '!build.js.cjs',
+    'test.unit.cjs/ci'
+  ];
 
-  buildAndTest();
-
-  watch('modules/**', buildAndTest);
+  watch('modules/**', { ignoreInitial: false }, buildAndTest);
 });
 
 
 gulp.task('test.unit.tools/ci', function(done) {
   fork('./tools/traceur-jasmine', ['dist/tools/**/*.spec.js'], {
     stdio: 'inherit'
-  }).on('close', done);
+  }).on('close', done.bind(null, null));
 });
 
 
 gulp.task('test.unit.tools', ['build/clean.tools'],  function(done) {
-  function buildAndTest() {
-    runSequence(
-      '!build.tools',
-      'test.unit.tools/ci'
-    );
-  }
+  var buildAndTest = [
+    '!build.tools',
+    'test.unit.tools/ci'
+  ];
 
-  buildAndTest();
-
-  watch('tools/**', buildAndTest);
+  watch(['tools/**', '!tools/**/test-fixtures/**'], {ignoreInitial: false}, buildAndTest);
 });
 
 

tools/build/watch.js

@@ -0,0 +1,83 @@
+var chokidar = require('chokidar');
+var runSequence = require('run-sequence');
+var path = require('path');
+
+function watch(globs, opts, tasks) {
+  if (typeof opts !== 'object' || Array.isArray(opts)) {
+    tasks = opts;
+    opts = {};
+  }
+
+  var useRunSequence = typeof tasks !== 'function';
+  var runTasks;
+
+  if (useRunSequence) {
+    if (!Array.isArray(tasks)) tasks = [tasks];
+    tasks = tasks.slice();
+    tasks.push(tasksDone);
+    runTasks = function runTaskSequence() {
+      runSequence.apply(null, tasks);
+    }
+  } else {
+    var sync = tasks.length === 0;
+    runTasks = function runCallback() {
+      try {
+        tasks(tasksDone);
+        if (sync) tasksDone();
+      } catch (e) {
+        return tasksDone(e);
+      }
+    }
+  }
+
+  var events = opts.events = opts.events || ['add', 'change', 'unlink'];
+  if (opts.ignoreInitial === undefined) opts.ignoreInitial = true;
+  var delay = opts.delay;
+  if (delay === undefined) delay = 100;
+
+  var watcher = chokidar.watch(globs, opts).
+      on('all', handleEvent).
+      on('error', function(err) {
+        throw err;
+      });
+
+  var close = watcher.close.bind(watcher);
+  watcher.close = function() {
+    if (timeoutId !== null) clearTimeout(timeoutId);
+    close();
+  }
+
+  var eventsRecorded = 0; // Number of events recorded
+  var timeoutId = null; // If non-null, event capture window is open
+
+  return watcher;
+
+  function handleEvent(event, filepath) {
+    // Ignore unwatched events
+    if (events.indexOf(event) < 0) return;
+
+    // Increment number of events captured in this window
+    ++eventsRecorded;
+
+    if (timeoutId === null) {
+      timeoutId = setTimeout(invokeCallback, delay);
+    }
+  }
+
+  function invokeCallback() {
+    eventsRecorded = 0;
+    runTasks();
+  }
+
+  function tasksDone(err) {
+    if (err) throw err;
+    if (eventsRecorded) {
+      // eventsRecorded has increased during the run, run again on the next turn
+      timeoutId = setTimeout(invokeCallback, 0);
+    } else {
+      timeoutId = null;
+    }
+  }
+}
+
+module.exports = watch;