From a26acfec5b4ed30053281fa10be8f77163ed5150 Mon Sep 17 00:00:00 2001
From: lukasz <lukasz.usarz@gmail.com>
Date: Sun, 22 Apr 2018 15:39:28 +0200
Subject: [PATCH] refactor(watcher): refactor watcher.js

---
 lib/watcher.js | 130 ++++++++++++++++++++-----------------------------
 1 file changed, 52 insertions(+), 78 deletions(-)

diff --git a/lib/watcher.js b/lib/watcher.js
index 284a45088..0af95c0e5 100644
--- a/lib/watcher.js
+++ b/lib/watcher.js
@@ -1,118 +1,92 @@
-var chokidar = require('chokidar')
-var mm = require('minimatch')
-var expandBraces = require('expand-braces')
+'use strict'
 
-var helper = require('./helper')
-var log = require('./logger').create('watcher')
+const chokidar = require('chokidar')
+const mm = require('minimatch')
+const expandBraces = require('expand-braces')
 
-var DIR_SEP = require('path').sep
+const helper = require('./helper')
+const log = require('./logger').create('watcher')
 
-// Get parent folder, that be watched (does not contain any special globbing character)
-var baseDirFromPattern = function (pattern) {
+const DIR_SEP = require('path').sep
+
+function baseDirFromPattern (pattern) {
   return pattern
-    .replace(/[/\\][^/\\]*\*.*$/, '')              // remove parts with *
-    .replace(/[/\\][^/\\]*[!+]\(.*$/, '')         // remove parts with !(...) and +(...)
+    .replace(/[/\\][^/\\]*\*.*$/, '') // remove parts with *
+    .replace(/[/\\][^/\\]*[!+]\(.*$/, '') // remove parts with !(...) and +(...)
     .replace(/[/\\][^/\\]*\)\?.*$/, '') || DIR_SEP // remove parts with (...)?
 }
 
-var watchPatterns = function (patterns, watcher) {
-  // filter only unique non url patterns paths
-  var pathsToWatch = []
-  var uniqueMap = {}
-  var path
+function watchPatterns (patterns, watcher) {
+  let pathsToWatch = new Set()
 
   // expand ['a/{b,c}'] to ['a/b', 'a/c']
-  patterns = expandBraces(patterns)
-
-  patterns.forEach(function (pattern) {
-    path = baseDirFromPattern(pattern)
-    if (!uniqueMap[path]) {
-      uniqueMap[path] = true
-      pathsToWatch.push(path)
-    }
-  })
+  expandBraces(patterns)
+    .forEach(path => pathsToWatch.add(baseDirFromPattern(path)))
 
+  pathsToWatch = Array.from(pathsToWatch)
   // watch only common parents, no sub paths
-  pathsToWatch.forEach(function (path) {
-    if (!pathsToWatch.some(function (p) {
-      return p !== path && path.substr(0, p.length + 1) === p + DIR_SEP
-    })) {
+  pathsToWatch.forEach(path => {
+    if (!pathsToWatch.some(p => p !== path && path.substr(0, p.length + 1) === p + DIR_SEP)) {
       watcher.add(path)
       log.debug('Watching "%s"', path)
     }
   })
 }
 
-// Function to test if a path should be ignored by chokidar.
-var createIgnore = function (patterns, excludes) {
+function checkAnyPathMatch (patterns, path) {
+  return patterns.some(pattern => mm(path, pattern, {dot: true}))
+}
+
+function createIgnore (patterns, excludes) {
   return function (path, stat) {
     if (!stat || stat.isDirectory()) {
       return false
     }
 
-    // Check if the path matches any of the watched patterns.
-    if (!patterns.some(function (pattern) {
-      return mm(path, pattern, {dot: true})
-    })) {
-      return true
-    }
-
-    // Check if the path matches any of the exclude patterns.
-    if (excludes.some(function (pattern) {
-      return mm(path, pattern, {dot: true})
-    })) {
-      return true
-    }
-
-    return false
+    return !checkAnyPathMatch(patterns, path) || checkAnyPathMatch(excludes, path)
   }
 }
 
-var onlyWatchedTrue = function (pattern) {
-  return pattern.watched
-}
-
-var getWatchedPatterns = function (patternObjects) {
-  return patternObjects.filter(onlyWatchedTrue).map(function (patternObject) {
-    return patternObject.pattern
-  })
+function getWatchedPatterns (patterns) {
+  return patterns
+    .reduce((array, pattern) => {
+      if (pattern.watched) {
+        array.push(pattern.pattern)
+      }
+      return array
+    }, [])
 }
 
 exports.watch = function (patterns, excludes, fileList, usePolling, emitter) {
-  var watchedPatterns = getWatchedPatterns(patterns)
-  var options = {
+  const watchedPatterns = getWatchedPatterns(patterns)
+
+  const watcher = new chokidar.FSWatcher({
     usePolling: usePolling,
     ignorePermissionErrors: true,
     ignoreInitial: true,
     ignored: createIgnore(watchedPatterns, excludes)
-  }
-  var chokidarWatcher = new chokidar.FSWatcher(options)
+  })
 
-  watchPatterns(watchedPatterns, chokidarWatcher)
+  watchPatterns(watchedPatterns, watcher)
 
-  var bind = function (fn) {
-    return function (path) {
-      return fn.call(fileList, helper.normalizeWinPath(path))
-    }
-  }
+  watcher
+    .on('add', path => fileList.addFile(helper.normalizeWinPath(path)))
+    .on('change', path => fileList.changeFile(helper.normalizeWinPath(path)))
+    .on('unlink', path => fileList.removeFile(helper.normalizeWinPath(path)))
+    .on('error', log.debug.bind(log))
 
-  // register events
-  chokidarWatcher.on('add', bind(fileList.addFile))
-    .on('change', bind(fileList.changeFile))
-    .on('unlink', bind(fileList.removeFile))
-    // If we don't subscribe; unhandled errors from Chokidar will bring Karma down
-    // (see GH Issue #959)
-    .on('error', function (e) {
-      log.debug(e)
-    })
-
-  emitter.on('exit', function (done) {
-    chokidarWatcher.close()
+  emitter.on('exit', done => {
+    watcher.close()
     done()
   })
 
-  return chokidarWatcher
+  return watcher
 }
 
-exports.watch.$inject = ['config.files', 'config.exclude', 'fileList', 'config.usePolling',
-  'emitter']
+exports.watch.$inject = [
+  'config.files',
+  'config.exclude',
+  'fileList',
+  'config.usePolling',
+  'emitter'
+]