feat(watcher): Allow using braces in watcher

Expands braces in watcher, so you can watch: ['a/{b,c}'] which would
expand to ['a/b', 'a/c']

Closes #1249

lib/watcher.js

@@ -1,5 +1,6 @@
 var chokidar = require('chokidar');
 var mm = require('minimatch');
+var expandBraces = require('expand-braces');
 
 var helper = require('./helper');
 var log = require('./logger').create('watcher');
@@ -19,6 +20,9 @@ var watchPatterns = function(patterns, watcher) {
   var uniqueMap = {};
   var path;
 
+  // expand ['a/{b,c}'] to ['a/b', 'a/c']
+  patterns = expandBraces(patterns);
+
   patterns.forEach(function(pattern) {
     path = baseDirFromPattern(pattern);
     if (!uniqueMap[path]) {

package.json

@@ -167,6 +167,7 @@
     "chokidar": ">=0.8.2",
     "glob": "~3.2.7",
     "minimatch": "~0.2",
+    "expand-braces": "~0.1.1",
     "http-proxy": "~0.10",
     "optimist": "~0.6.0",
     "rimraf": "~2.2.5",

test/unit/watcher.spec.coffee

@@ -59,11 +59,21 @@ describe 'watcher', ->
       expect(chokidarWatcher.watchedPaths_).to.deep.equal ['/some', '/a']
 
 
+    it 'should expand braces and watch all the patterns', ->
+      m.watchPatterns ['/some/{a,b}/*.js', '/a/*'], chokidarWatcher
+      expect(chokidarWatcher.watchedPaths_).to.deep.equal ['/some/a', '/some/b', '/a']
+
+
     it 'should not watch the same path twice', ->
       m.watchPatterns ['/some/a*.js', '/some/*.txt'], chokidarWatcher
       expect(chokidarWatcher.watchedPaths_).to.deep.equal ['/some']
 
 
+    it 'should not watch the same path twice when using braces', ->
+      m.watchPatterns ['/some/*.{js,txt}'], chokidarWatcher
+      expect(chokidarWatcher.watchedPaths_).to.deep.equal ['/some']
+
+
     it 'should not watch subpaths that are already watched', ->
       m.watchPatterns ['/some/sub/*.js', '/some/a*.*'].map(path.normalize), chokidarWatcher
       expect(chokidarWatcher.watchedPaths_).to.deep.equal [path.normalize('/some')]
@@ -75,6 +85,11 @@ describe 'watcher', ->
       expect(chokidarWatcher.watchedPaths_).to.deep.equal ['/some/test-file.js', '/some/test']
 
 
+    it 'should watch files matching a subpath directory with braces', ->
+      m.watchPatterns ['/some/{a,b}/test.js'], chokidarWatcher
+      expect(chokidarWatcher.watchedPaths_).to.deep.equal ['/some/a/test.js', '/some/b/test.js']
+
+
   describe 'getWatchedPatterns', ->
 
     it 'should return list of watched patterns (strings)', ->