Fully refactored the watcher

lib/watch/index.mjs

@@ -1,20 +1,14 @@
 import fs from 'fs'
+import fsPromise from 'fs/promises'
 import path from 'path'
-import util from 'util'
 import events from 'events'
 import hasNativeRecursive from './has-native-recursive.mjs'
 import * as is from './is.mjs'
 
 const EVENT_UPDATE = 'update';
 const EVENT_REMOVE = 'remove';
-
+const TYPE_FILE = 'file'
-const SKIP_FLAG = Symbol('skip');
+const TYPE_DIRECTORY = 'directory'
-
-function hasDup(arr) {
-  return arr.some(function(v, i, self) {
-    return self.indexOf(v) !== i;
-  });
-}
 
 function unique(arr) {
   return arr.filter(function(v, i, self) {
@@ -22,528 +16,274 @@ function unique(arr) {
   });
 }
 
-// One level flat
+export default class Watcher extends events.EventEmitter {
-function flat1(arr) {
+  constructor(path, options = null, fn = null, { fs: fsoverwrite } = {}) {
-  return arr.reduce(function(acc, v) {
+    super()
-    return acc.concat(v);
-  }, []);
-}
 
-function assertEncoding(encoding) {
+    this.ac = new AbortController()
-  if (encoding && encoding !== 'buffer' && !Buffer.isEncoding(encoding)) {
+    events.setMaxListeners(2000, this.ac.signal)
-    throw new Error('Unknown encoding: ' + encoding);
+    this._fs = fsoverwrite || fs
+    this._cache = []
+    this._cacheTimeout = null
+    this.listeners = []
+    this.closed = false
+    let paths = path
+    if (is.buffer(paths)) {
+      paths = paths.toString()
     }
-}
 
-function guard(fn) {
+    if (!is.array(paths)) {
-  if (is.func(fn)) {
+      paths = [paths]
-    return function(arg, action) {
-      if (fn(arg, false)) action();
     }
-  }
-  if (is.regExp(fn)) {
-    return function(arg, action) {
-      if (fn.test(arg)) action();
-    }
-  }
-  return function(arg, action) {
-    action();
-  }
-}
 
-function composeMessage(names) {
+    paths = unique(paths)
-  return names.map(function(n) {
+    this.options = options || {}
-    return is.exists(n)
+    this.fn = fn || null
-      ? [EVENT_UPDATE, n]
-      : [EVENT_REMOVE, n];
-  });
-}
 
-function getMessages(cache) {
+    if (is.func(this.options)) {
-  var filtered = unique(cache);
+      this.fn = this.options
+      this.options = {}
+    }
 
-  // Saving file from an editor? If so, assuming the
+    this._verifyOptions(paths)
-  // non-existed files in the cache are temporary files
+  }
-  // generated by an editor and thus be filtered.
-  var reg = /~$|^\.#|^##$/g;
-  var hasSpecialChar = cache.some(function(c) {
-    return reg.test(c);
-  });
 
-  if (hasSpecialChar) {
+  isClosed() {
-    var dup = hasDup(cache.map(function(c) {
+    return this.closed
-      return c.replace(reg, '');
+  }
-    }));
+
-    if (dup) {
+  close() {
-      filtered = filtered.filter(function(m) {
+    this.closed = true
-        return is.exists(m);
+    this.ac.abort()
-      });
+    this._cache = this.listeners = []
+    
+    this.emitAsync('close')
+  }
+
+  emitAsync(name, ...args) {
+    process.nextTick(() => this.emit(name, ...args))
+  }
+
+  _verifyOptions(paths) {
+    for (let path of paths) {
+      if (!is.exists(path)) {
+        this.emitAsync('error', new Error(path + ' does not exist.'))
       }
     }
 
-  return composeMessage(filtered);
+    if (this.options.encoding) {
-}
+      if (this.options.encoding && this.options.encoding !== 'buffer' && !Buffer.isEncoding(this.options.encoding)) {
+        throw new Error('Unknown encoding: ' + this.options.encoding);
+      }
+    } else {
+      this.options.encoding = 'utf8'
+    }
 
-function debounce(info, fn) {
+    if (this.options.delay !== 0 && !this.options.delay) {
-  var timer, cache = [];
+      this.options.delay = 200
-  var encoding = info.options.encoding;
-  var delay = info.options.delay;
-  if (!is.number(delay)) {
-    delay = 200;
     }
-  function handle() {
-    getMessages(cache).forEach(function(msg) {
-      msg[1] = Buffer.from(msg[1]);
-      if (encoding !== 'buffer') {
-        msg[1] = msg[1].toString(encoding);
-      }
-      fn.apply(null, msg);
-    });
-    timer = null;
-    cache = [];
-  }
-  return function(rawEvt, name) {
-    cache.push(name);
-    if (!timer) {
-      timer = setTimeout(handle, delay);
-    }
-  }
-}
 
-function createDupsFilter() {
+    if (is.func(this.fn)) {
-  var memo = {};
+      this.on('change', this.fn)
-  return function(fn) {
-    return function(evt, name) {
-      memo[evt + name] = [evt, name];
-      setTimeout(function() {
-        Object.keys(memo).forEach(function(n) {
-          fn.apply(null, memo[n]);
-        });
-        memo = {};
-      });
     }
-  }
-}
     
-function tryWatch(watcher, dir, opts) {
+    if (this.options.manualRecursive !== true) {
+      hasNativeRecursive(nativeRecursive => {
+        this.supportsNativeRecursive = nativeRecursive
+        this.options.manualRecursive = !nativeRecursive
+        this._startListeners(paths)
+      })
+    } else {
+      this._startListeners(paths)
+    }
+  }
+
+  _startListeners(paths) {
+    Promise.all(paths.map(path => this.safeAdd(path)))
+    .then(
+      () => this.emit('ready'),
+      err => this.emit('error', err),
+    )
+  }
+
+  getWatcherOrNull(name) {
+    for (let check of this.listeners) {
+      if (check.path === name) {
+        return check
+      }
+    }
+    return null
+  }
+
+  shouldInclude(name) {
+    return this.options.filter
+      ? 
+        (is.func(this.options.filter) && this.options.filter.call(this, name) === true)
+        || (is.regExp(this.options.filter) && this.options.filter.test(name))
+      : true
+  }
+
+  closeWatch(orgItem) {
+    let item = orgItem
+    if (typeof item === 'string') {
+      item = getWatcherOrNull(item)
+    }
+    if (!item) {
+      this.emit('error', new Error(`attempted to close watcher for ${item} but such a watcher could not be found`))
+      return
+    }
+
+    if (item.watcher) {
+      item.watcher.close()
+    }
+
+    this._emitEvent(item, EVENT_REMOVE, item.path)
+    let index = this.listeners.indexOf(item)
+    if (index < 0) return
+    this.listeners.splice(index, 1)
+  }
+
+  _emitEvent(item, evt, name) {
+    if (item.type === TYPE_FILE && !is.samePath(name, item.filename)) return
+    if (item.type === TYPE_DIRECTORY && !this.shouldInclude(name)) return
+
+    if (item.flag) {
+      item.flag = ''
+      return
+    }
+
+    let outputName = name
+
+    if (this.options.encoding !== 'utf8') {
+      outputName = Buffer.from(outputName)
+
+      if (this.options.encoding !== 'buffer') {
+        outputName = outputName.toString(this.options.encoding)
+      }
+    }
+
+    if (!this.options.delay) {
+      this.emit('change', evt, outputName)
+      return
+    }
+
+    this._cache.push([evt, name, outputName])
+
+    if (this._cacheTimeout) return
+
+    this._cacheTimeout = setTimeout(() => {
+      let cache = this._filterCache(this._cache)
+      this._cache = []
+      this._cacheTimeout = null
+
+      for (let event of cache) {
         try {
-    return fs.watch(dir, opts);
+          this.emit('change', event[0], event[2])
-  } catch (e) {
+        } catch (err) {
-    process.nextTick(function() {
+          this.emit('error', err)
-      watcher.emit('error', e);
+        }
-    });
+      }
+    }, this.options.delay)
   }
-}
 
-function getSubDirectories(dir, fn, done = function() {}) {
+  _filterCache(cache) {
-  if (is.directory(dir)) {
+    let setFound = new Set()
-    fs.readdir(dir, function(err, all) {
+
-      if (err) {
+    let out = cache.reverse().filter(([evt, name]) => {
-        // don't throw permission errors.
+      if (setFound.has(name)) return false
-        if (/^(EPERM|EACCES)$/.test(err.code)) {
+      setFound.add(name)
-          console.warn('Warning: Cannot access %s.', dir);
+      return true
+    }).reverse()
+    return out
+  }
+
+  _watcherSink(item, rawEvt, rawName) {
+    if (this.closed) return
+
+    let name = path.join(item.path, rawName || '')
+    let evt = is.exists(name) ? EVENT_UPDATE : EVENT_REMOVE
+
+    if (this.options.recursive && this.options.manualRecursive && item.type === TYPE_DIRECTORY) {
+      if (evt === EVENT_REMOVE) {
+        this.closeWatch(name)
+        return
       } else {
-          throw err;
+        if (is.directory(name)
+            && this.getWatcherOrNull(name) === null
+            && this.shouldInclude(name) === false) {
+          this.safeAdd(subItem, TYPE_DIRECTORY)
         }
       }
-      else {
-        all.forEach(function(f) {
-          var sdir = path.join(dir, f);
-          if (is.directory(sdir)) fn(sdir);
-        });
-        done();
     }
-    });
+
+    this._emitEvent(item, evt, name)
+  }
+
+  _pathToItem(name, type) {
+    if (type === TYPE_FILE) {
+      let parent = path.join(name, '../')
+      return {
+        path: parent,
+        type: TYPE_FILE,
+        filename: name,
+        watcher: null,
+        flag: '',
+      }
     } else {
-    done();
+      return {
-  }
+        path: name,
-}
+        type: TYPE_DIRECTORY,
-
+        watcher: null,
-function semaphore(final) {
+        flag: '',
-  var counter = 0;
-  return function start() {
-    counter++;
-    return function stop() {
-      counter--;
-      if (counter === 0) final();
-    };
-  };
-}
-
-function nullCounter() {
-  return function nullStop() {};
-}
-
-function shouldNotSkip(filePath, filter) {
-  // watch it only if the filter is not function
-  // or not being skipped explicitly.
-  return !is.func(filter) || filter(filePath, SKIP_FLAG) !== SKIP_FLAG;
-}
-
-var deprecationWarning = util.deprecate(
-  function() {},
-  '(node-watch) First param in callback function\
-  is replaced with event name since 0.5.0, use\
-  `(evt, filename) => {}` if you want to get the filename'
-);
-
-function Watcher() {
-  events.EventEmitter.call(this);
-  this.watchers = {};
-  this._isReady = false;
-  this._isClosed = false;
-}
-
-util.inherits(Watcher, events.EventEmitter);
-
-Watcher.prototype.expose = function() {
-  var expose = {};
-  var self = this;
-  var methods = [
-    'on', 'emit', 'once',
-    'close', 'isClosed',
-    'listeners', 'setMaxListeners', 'getMaxListeners',
-    'getWatchedPaths'
-  ];
-  methods.forEach(function(name) {
-    expose[name] = function() {
-      return self[name].apply(self, arguments);
-    }
-  });
-  expose.options = self.options
-  return expose;
-}
-
-Watcher.prototype.isClosed = function() {
-  return this._isClosed;
-}
-
-Watcher.prototype.close = function(fullPath) {
-  var self = this;
-  if (fullPath) {
-    var watcher = this.watchers[fullPath];
-    if (watcher && watcher.close) {
-      watcher.close();
-      delete self.watchers[fullPath];
-    }
-    getSubDirectories(fullPath, function(fpath) {
-      self.close(fpath);
-    });
-  }
-  else {
-    Object.keys(self.watchers).forEach(function(fpath) {
-      var watcher = self.watchers[fpath];
-      if (watcher && watcher.close) {
-        watcher.close();
-      }
-    });
-    this.watchers = {};
-  }
-  // Do not close the Watcher unless all child watchers are closed.
-  // https://github.com/yuanchuan/node-watch/issues/75
-  if (is.emptyObject(self.watchers)) {
-    // should emit once
-    if (!this._isClosed) {
-      this._isClosed = true;
-      process.nextTick(emitClose, this);
       }
     }
-}
-
-Watcher.prototype.getWatchedPaths = function(fn) {
-  if (is.func(fn)) {
-    var self = this;
-    if (self._isReady) {
-      fn(Object.keys(self.watchers));
-    } else {
-      self.on('ready', function() {
-        fn(Object.keys(self.watchers));
-      });
-    }
-  }
-}
-
-function emitReady(self) {
-  if (!self._isReady) {
-    self._isReady = true;
-    // do not call emit for 'ready' until after watch() has returned,
-    // so that consumer can call on().
-    process.nextTick(function () {
-      self.emit('ready');
-    });
-  }
-}
-
-function emitClose(self) {
-  self.emit('close');
-}
-
-Watcher.prototype.add = function(watcher, info) {
-  var self = this;
-  info = info || { fpath: '' };
-  var watcherPath = path.resolve(info.fpath);
-  this.watchers[watcherPath] = watcher;
-
-  // Internal callback for handling fs.FSWatcher 'change' events
-  var internalOnChange = function(rawEvt, rawName) {
-    if (self.isClosed()) {
-      return;
   }
 
-    // normalise lack of name and convert to full path
+  _watcherError(item, err) {
-    var name = rawName;
+    if (this.closed) return
-    if (is.nil(name)) {
-      name = '';
-    }
-    name = path.join(info.fpath, name);
     
-    if (info.options.recursive) {
-      hasNativeRecursive(function(has) {
-        if (!has) {
-          var fullPath = path.resolve(name);
-          // remove watcher on removal
-          if (!is.exists(name)) {
-            self.close(fullPath);
-          }
-          // watch new created directory
-          else {
-            var shouldWatch = is.directory(name)
-              && !self.watchers[fullPath]
-              && shouldNotSkip(name, info.options.filter);
-
-            if (shouldWatch) {
-              self.watchDirectory(name, info.options);
-            }
-          }
-        }
-      });
-    }
-
-    handlePublicEvents(rawEvt, name);
-  };
-
-  // Debounced based on the 'delay' option
-  var handlePublicEvents = debounce(info, function (evt, name) {
-    // watch single file
-    if (info.compareName) {
-      if (info.compareName(name)) {
-        self.emit('change', evt, name);
-      }
-    }
-    // watch directory
-    else {
-      var filterGuard = guard(info.options.filter);
-      filterGuard(name, function() {
-        if (self.flag) self.flag = '';
-        else self.emit('change', evt, name);
-      });
-    }
-  });
-
-  watcher.on('error', function(err) {
-    if (self.isClosed()) {
-      return;
-    }
     if (is.windows() && err.code === 'EPERM') {
-      watcher.emit('change', EVENT_REMOVE, info.fpath && '');
+      this.closeWatch(item)
-      self.flag = 'windows-error';
+      item.flag = 'windows-error'
-      self.close(watcherPath);
     } else {
-      self.emit('error', err);
+      self.emit('error', err)
     }
-  });
-
-  watcher.on('change', internalOnChange);
-}
-
-Watcher.prototype.watchFile = function(file, options, fn) {
-  var parent = path.join(file, '../');
-  var opts = Object.assign({}, options, {
-    // no filter for single file
-    filter: null,
-    encoding: 'utf8'
-  });
-
-  // no need to watch recursively
-  delete opts.recursive;
-
-  var watcher = tryWatch(this, parent, opts);
-  if (!watcher) {
-    return;
   }
 
-  this.add(watcher, {
+  safeAdd(name, orgType) {
-    type: 'file',
+    let type = orgType
-    fpath: parent,
+    if (!type) {
-    options: Object.assign({}, opts, {
+      type = is.file(name) ? TYPE_FILE : TYPE_DIRECTORY
-      encoding: options.encoding
-    }),
-    compareName: function(n) {
-      return is.samePath(n, file);
     }
-  });
 
-  if (is.func(fn)) {
+    let item = this._pathToItem(name, type)
-    if (fn.length === 1) deprecationWarning();
+    let options = {
-    this.on('change', fn);
+      encoding: 'utf8',
+      signal: this.ac.signal,
+    }
+    if (!this.options.manualRecursive && item.type !== TYPE_FILE && this.options.recursive) {
+      options.recursive = true
+    }
+
+    try {
+      item.watcher = this._fs.watch(item.path, options)
+    } catch (err) {
+      this.emitAsync('error', err)
+    }
+
+    if (!item.watcher) return
+    
+    this.listeners.push(item)
+
+    item.watcher.on('error', this._watcherError.bind(this, item))
+    item.watcher.on('change', this._watcherSink.bind(this, item))
+
+    if (options.recursive || item.type === TYPE_FILE) return
+
+    return fsPromise.readdir(item.path, { withFileTypes: true })
+      .then(directories => directories.filter(dir => dir.isDirectory()))
+      .then(directories => {
+        return Promise.all(directories.map(dir => this.safeAdd(path.join(item.path, dir.name), TYPE_DIRECTORY)))
+      })
   }
 }
-
-Watcher.prototype.updateDelay = function(delay) {
-  console.log()
-}
-
-Watcher.prototype.watchDirectory = function(dir, options, fn, counter = nullCounter) {
-  var self = this;
-  var done = counter();
-  hasNativeRecursive(function(has) {
-    // always specify recursive
-    options.recursive = !!options.recursive;
-    // using utf8 internally
-    var opts = Object.assign({}, options, {
-      encoding: 'utf8'
-    });
-    if (!has) {
-      delete opts.recursive;
-    }
-
-    // check if it's closed before calling watch.
-    if (self._isClosed) {
-      done();
-      return self.close();
-    }
-
-    var watcher = tryWatch(self, dir, opts);
-    if (!watcher) {
-      done();
-      return;
-    }
-
-    self.add(watcher, {
-      type: 'dir',
-      fpath: dir,
-      options: options
-    });
-
-    if (is.func(fn)) {
-      if (fn.length === 1) deprecationWarning();
-      self.on('change', fn);
-    }
-
-    if (options.recursive && !has) {
-      getSubDirectories(dir, function(d) {
-        if (shouldNotSkip(d, options.filter)) {
-          self.watchDirectory(d, options, null, counter);
-        }
-      }, counter());
-    }
-
-    done();
-  });
-}
-
-function composeWatcher(watchers) {
-  var watcher = new Watcher();
-  var filterDups = createDupsFilter();
-  var counter = watchers.length;
-
-  watchers.forEach(function(w) {
-    w.on('change', filterDups(function(evt, name) {
-      watcher.emit('change', evt, name);
-    }));
-    w.on('error', function(err) {
-      watcher.emit('error', err);
-    });
-    w.on('ready', function() {
-      if (!(--counter)) {
-        emitReady(watcher);
-      }
-    });
-  });
-
-  watcher.close = function() {
-    watchers.forEach(function(w) {
-      w.close();
-    });
-    process.nextTick(emitClose, watcher);
-  }
-
-  watcher.getWatchedPaths = function(fn) {
-    if (is.func(fn)) {
-      var promises = watchers.map(function(w) {
-        return new Promise(function(resolve) {
-          w.getWatchedPaths(resolve);
-        });
-      });
-      Promise.all(promises).then(function(result) {
-        var ret = unique(flat1(result));
-        fn(ret);
-      });
-    }
-  }
-
-  return watcher.expose();
-}
-
-export default function watch(fpath, options, fn) {
-  var watcher = new Watcher();
-
-  if (is.buffer(fpath)) {
-    fpath = fpath.toString();
-  }
-
-  if (!is.array(fpath) && !is.exists(fpath)) {
-    process.nextTick(function() {
-      watcher.emit('error',
-        new Error(fpath + ' does not exist.')
-      );
-    });
-  }
-
-  if (is.string(options)) {
-    throw new Error(`Invalid option, encoding as string is no longer supported. Use { encoding: "${options}" } instead.`)
-  }
-
-  if (is.func(options)) {
-    fn = options;
-    options = {};
-  }
-
-  if (arguments.length < 2) {
-    options = {};
-  }
-
-  if (options.encoding) {
-    assertEncoding(options.encoding);
-  } else {
-    options.encoding = 'utf8';
-  }
-
-  if (is.array(fpath)) {
-    if (fpath.length === 1) {
-      return watch(fpath[0], options, fn);
-    }
-    var filterDups = createDupsFilter();
-    return composeWatcher(unique(fpath).map(function(f) {
-      var w = watch(f, options);
-      if (is.func(fn)) {
-        w.on('change', filterDups(fn));
-      }
-      return w;
-    }));
-  }
-
-  if (is.file(fpath)) {
-    watcher.watchFile(fpath, options, fn);
-    emitReady(watcher);
-  }
-
-  else if (is.directory(fpath)) {
-    var counter = semaphore(function () {
-      emitReady(watcher);
-    });
-    watcher.watchDirectory(fpath, options, fn, counter);
-  }
-
-  return watcher.expose();
-}

test/cli.test.mjs

@@ -185,7 +185,6 @@ t.describe('CLI', function() {
       cli.targets = ['test/testtree/*/*.mjs']
       await cli.processTargets()
 
-      console.log(cli.files)
       assert.strictEqual(cli.files.length, 4)
       cli.files.sort()
       assert.deepEqual(cli.files, [

test/watch.test.mjs

@@ -1,10 +1,9 @@
 import path from 'path'
+import fs from 'fs'
 import assert from '../lib/assert.mjs'
 import t from '../lib/eltro.mjs'
 import { Builder, Counter } from './watch/builder.mjs'
-import watch from '../lib/watch/index.mjs'
+import Watcher from '../lib/watch/index.mjs'
-import * as is from '../lib/watch/is.mjs'
-import hasNativeRecursive from '../lib/watch/has-native-recursive.mjs'
 
 const builder = new Builder()
 let watcher
@@ -32,27 +31,12 @@ t.after(function() {
   }
 })
 
-function wait(fn, timeout) {
+t.describe('watcher', function() {
-  try {
-    fn()
-  } catch (error) {
-    timeout -= 30
-    if (timeout >= 0) {
-      setTimeout(function() {
-        wait(fn, timeout)
-      }, 30)
-    } else {
-      throw error
-    }
-  }
-}
-
-t.only().describe('watcher', function() {
   t.describe('process events', function() {
     t.test('should emit `close` event', function(done) {
       var file = 'home/a/file1'
       var fpath = builder.getPath(file)
-      watcher = watch(fpath, function() {})
+      watcher = new Watcher(fpath, function() {})
       watcher.on('close', done)
       watcher.close()
     })
@@ -60,13 +44,13 @@ t.only().describe('watcher', function() {
     t.test('should emit `ready` event when watching a file', function(done) {
       var file = 'home/a/file1'
       var fpath = builder.getPath(file)
-      watcher = watch(fpath)
+      watcher = new Watcher(fpath)
       watcher.on('ready', done)
     })
 
     t.test('should emit `ready` event when watching a directory recursively', function(done) {
       var dir = builder.getPath('home')
-      watcher = watch(dir, { recursive: true })
+      watcher = new Watcher(dir, { recursive: true })
       watcher.on('ready', done)
     })
 
@@ -74,7 +58,7 @@ t.only().describe('watcher', function() {
       var dir1 = builder.getPath('home/a')
       var dir2 = builder.getPath('home/b')
       var file = builder.getPath('home/b/file1')
-      watcher = watch([dir1, dir2, file], { recursive: true })
+      watcher = new Watcher([dir1, dir2, file], { recursive: true })
       watcher.on('ready', done)
     })
   })
@@ -84,7 +68,7 @@ t.only().describe('watcher', function() {
       var counter = new Counter(done, 3)
       var file = 'home/a/file1'
       var fpath = builder.getPath(file)
-      watcher = watch(fpath, { delay: 0 }, function(evt, name) {
+      watcher = new Watcher(fpath, { delay: 0 }, function(evt, name) {
         assert.strictEqual(fpath, name)
         counter.count()
       })
@@ -105,7 +89,7 @@ t.only().describe('watcher', function() {
         builder.newFile('home/a/file1'),
         builder.newFile('home/a/file2'),
       ]).then(() => {
-        watcher = watch(fpath, { delay: 0 }, function(evt, name) {
+        watcher = new Watcher(fpath, { delay: 0 }, function(evt, name) {
           set.delete(name)
           if (!set.size) {
             done()
@@ -130,7 +114,7 @@ t.only().describe('watcher', function() {
       var middle = start
       var end = start
       
-      watcher = watch(fpath, { delay: 100 }, function(evt, name) {
+      watcher = new Watcher(fpath, { delay: 100 }, function(evt, name) {
         if (fpath === name) counter.count()
       })
 
@@ -165,7 +149,7 @@ t.only().describe('watcher', function() {
       ])
       var changes = []
       var extra = []
-      watcher = watch(home, { delay: 0, recursive: true }, function(evt, name) {
+      watcher = new Watcher(home, { delay: 0, recursive: true }, function(evt, name) {
         if (set.has(name)) {
           changes.push(name)
           counter.count()
@@ -189,16 +173,14 @@ t.only().describe('watcher', function() {
       var fpath = builder.getPath('home/a/file1')
       builder.newFile('home/a/file1')
         .then(() => {
-          watcher = watch(fpath, Object.defineProperty({}, 'test', {
+          watcher = new Watcher(fpath, null, null, { fs: { watch: function(path, options) {
-            enumerable: true,
-            get: function() {
             builder.removeSync('home/a')
-              return 'test'
+            return fs.watch(path, options)
-            }
+          } } })
+
+          watcher.on('error', done.finish(function(err) {
+            assert.deepStrictEqual(watcher.listeners, [])
           }))
-          watcher.on('error', function() {
-            done()
-          })
         })
     })
   })
@@ -209,7 +191,7 @@ t.only().describe('watcher', function() {
       var dir = builder.getPath('home/c')
 
       builder.createDirectory('home/c').then(() => {
-        watcher = watch(home, { delay: 0, recursive: true }, function(evt, name) {
+        watcher = new Watcher(home, { delay: 0, recursive: true }, function(evt, name) {
           if (name === dir && evt === 'remove') {
             done()
           }
@@ -224,7 +206,7 @@ t.only().describe('watcher', function() {
       var home = builder.getPath('home')
 
       builder.remove('home/new').then(() => {
-        watcher = watch(home, { delay: 0, recursive: true }, function(evt, name) {
+        watcher = new Watcher(home, { delay: 0, recursive: true }, function(evt, name) {
           if (name === builder.getPath('home/new/file1')) {
             done()
           }
@@ -244,20 +226,21 @@ t.only().describe('watcher', function() {
       var options = {
         delay: 0,
         recursive: true,
-        filter: function(filePath, SKIP_FLAG) {
+        filter: function(filePath) {
           if (/ignored/.test(filePath)) {
             counter.count()
-            return SKIP_FLAG
-          }
             return false
           }
+          return true
+        }
       }
 
       builder.remove('home/ignored/file').then(() => {
-        watcher = watch(home, options, function(evt, name) {
+        watcher = new Watcher(home, options, function(evt, name) {
           assert.fail("should not watch new created directories which are being skipped in the filter event detect: " + name)
         })
 
+    
         watcher.on('ready', function() {
           builder.newFile('home/ignored/file')
             .catch(done)
@@ -279,7 +262,7 @@ t.only().describe('watcher', function() {
         builder.newFile('home/e/file2'),
       ]).then(() => {
 
-        watcher = watch(home, { delay: 0, recursive: true }, function(evt, name) {
+        watcher = new Watcher(home, { delay: 0, recursive: true }, function(evt, name) {
           if (name === dir || name === file1 || name === file2) {
             if (!set.has(name)) {
               set.add(name)
@@ -301,7 +284,7 @@ t.only().describe('watcher', function() {
       var home = builder.getPath('home')
 
       builder.remove('home/new').then(() => {
-        watcher = watch(home, { delay: 200, recursive: true }, function(evt, name) {
+        watcher = new Watcher(home, { delay: 200, recursive: true }, function(evt, name) {
           if (name === builder.getPath('home/new/file1')) {
             counter.count()
           }
@@ -319,16 +302,14 @@ t.only().describe('watcher', function() {
       var fpath = builder.getPath(dir)
 
       builder.createDirectory(dir).then(() => {
-        watcher = watch(fpath, Object.defineProperty({}, 'test', {
+        watcher = new Watcher(fpath, null, null, { fs: { watch: function(path, options) {
-          enumerable: true,
-          get: function() {
           builder.removeSync(dir)
-            return 'test'
+          return fs.watch(path, options)
-          }
+        } } })
+
+        watcher.on('error', done.finish(function(err) {
+          assert.deepStrictEqual(watcher.listeners, [])
         }))
-        watcher.on('error', function() {
-          done()
-        })
       })
     })
   })
@@ -342,7 +323,7 @@ t.only().describe('watcher', function() {
     })
 
     t.test('should identify `remove` event', function(done) {
-      watcher = watch(fpath, { delay: 0 }, function(evt, name) {
+      watcher = new Watcher(fpath, { delay: 0 }, function(evt, name) {
         if (evt === 'remove' && name === fpath) {
           done()
         }
@@ -357,7 +338,7 @@ t.only().describe('watcher', function() {
       var home = builder.getPath('home')
       var fpath = builder.getPath(dir)
 
-      watcher = watch(home, { delay: 0 }, function(evt, name) {
+      watcher = new Watcher(home, { delay: 0 }, function(evt, name) {
         if (evt === 'remove' && name === fpath) done()
       })
       watcher.on('ready', function() {
@@ -372,7 +353,7 @@ t.only().describe('watcher', function() {
       builder.newRandomFiles(dir, 100).then(names => {
         var counter = new Counter(done, names.length)
 
-        watcher = watch(fpath, { delay: 10 }, function(evt, name) {
+        watcher = new Watcher(fpath, { delay: 10 }, function(evt, name) {
           if (evt === 'remove') counter.count()
         })
 
@@ -386,7 +367,7 @@ t.only().describe('watcher', function() {
       var file = 'home/b/file1'
       var fpath = builder.getPath(file)
       builder.newFile(file).then(() => {
-        watcher = watch(fpath, { delay: 0 }, function(evt, name) {
+        watcher = new Watcher(fpath, { delay: 0 }, function(evt, name) {
           if (evt === 'update' && name === fpath) done()
         })
         watcher.on('ready', function() {
@@ -400,7 +381,7 @@ t.only().describe('watcher', function() {
       var file = 'home/a/newfile_' + builder.randomName()
       var fpath = builder.getPath(file)
 
-      watcher = watch(dir, { delay: 0 }, function(evt, name) {
+      watcher = new Watcher(dir, { delay: 0 }, function(evt, name) {
         if (evt === 'update' && name === fpath) done()
       })
       watcher.on('ready', function() {
@@ -414,7 +395,7 @@ t.only().describe('watcher', function() {
       t.test('should watch recursively with `recursive: true` option', function(done) {
         var dir = builder.getPath('home')
         var file = builder.getPath('home/bb/file1')
-        watcher = watch(dir, { delay: 0, recursive: true }, function(evt, name) {
+        watcher = new Watcher(dir, { delay: 0, recursive: true }, function(evt, name) {
           if (file === name) {
             done()
           }
@@ -442,7 +423,7 @@ t.only().describe('watcher', function() {
       t.test('should throw on invalid encoding', function(done) {
         options.encoding = 'unknown'
         try {
-          watcher = watch(fdir, options)
+          watcher = new Watcher(fdir, options)
         } catch (e) {
           done()
         }
@@ -450,7 +431,7 @@ t.only().describe('watcher', function() {
 
       t.test('should accept an encoding string', function(done) {
         options.encoding = 'utf8'
-        watcher = watch(fdir, options, done.finish(function(evt, name) {
+        watcher = new Watcher(fdir, options, done.finish(function(evt, name) {
           assert.strictEqual(name.toString(), fpath)
         }))
         watcher.on('ready', function() {
@@ -460,7 +441,7 @@ t.only().describe('watcher', function() {
 
       t.test('should support buffer encoding', function(done) {
         options.encoding = 'buffer'
-        watcher = watch(fdir, options, done.finish(function(evt, name) {
+        watcher = new Watcher(fdir, options, done.finish(function(evt, name) {
           assert.ok(Buffer.isBuffer(name), 'not a Buffer')
           assert.strictEqual(name.toString(), fpath)
         }))
@@ -472,7 +453,7 @@ t.only().describe('watcher', function() {
 
       t.test('should support base64 encoding', function(done) {
         options.encoding = 'base64'
-        watcher = watch(fdir, options, done.finish(function(evt, name) {
+        watcher = new Watcher(fdir, options, done.finish(function(evt, name) {
           assert.strictEqual(
             name,
             Buffer.from(fpath).toString('base64'),
@@ -486,7 +467,7 @@ t.only().describe('watcher', function() {
 
       t.test('should support hex encoding', function(done) {
         options.encoding = 'hex'
-        watcher = watch(fdir, options, done.finish(function(evt, name) {
+        watcher = new Watcher(fdir, options, done.finish(function(evt, name) {
           assert.strictEqual(
             name,
             Buffer.from(fpath).toString('hex'),
@@ -516,7 +497,7 @@ t.only().describe('watcher', function() {
           }
         }
 
-        watcher = watch(builder.getPath('home'), options, function(evt, name) {
+        watcher = new Watcher(builder.getPath('home'), options, function(evt, name) {
           if (/deep_node_modules/.test(name)) {
             matchIgnoredDir = true
           } else {
@@ -552,7 +533,7 @@ t.only().describe('watcher', function() {
 
         var times = 0
         var matchIgnoredFile = false
-        watcher = watch(dir, options, function(evt, name) {
+        watcher = new Watcher(dir, options, function(evt, name) {
           if (name === builder.getPath(file1)) {
             matchIgnoredFile = true
           }
@@ -585,7 +566,7 @@ t.only().describe('watcher', function() {
 
         var times = 0
         var matchIgnoredFile = false
-        watcher = watch(dir, options, function(evt, name) {
+        watcher = new Watcher(dir, options, function(evt, name) {
           if (name === builder.getPath(file1)) {
             matchIgnoredFile = true
           }
@@ -605,31 +586,21 @@ t.only().describe('watcher', function() {
         var options = {
           delay: 0,
           recursive: true,
+          manualRecursive: true,
           filter: function(name, skip) {
             if (/\/deep_node_modules/.test(name)) return skip
           }
         }
-        watcher = watch(home, options)
+        watcher = new Watcher(home, options)
 
-        watcher.getWatchedPaths(function(paths) {
+        watcher.on('ready', done.finish(function() {
-          hasNativeRecursive(function(supportRecursive) {
+          let homeFiltered = builder.getAllDirectories().filter(function(name) {
-            var watched = supportRecursive
-                // The skip flag has no effect to the platforms which support recursive option,
-                // so the home directory is the only one that's in the watching list.
-              ? [home]
-                // The deep_node_modules and all its subdirectories should not be watched
-                // with skip flag specified in the filter.
-              : builder.getAllDirectories().filter(function(name) {
             return !/\/deep_node_modules/.test(name)
-                })
+          }).sort()
+          let watchersPaths = watcher.listeners.map(x => x.path).sort()
 
-            assert.deepStrictEqual(
+          assert.deepStrictEqual(watchersPaths, homeFiltered)
-              watched.sort(), paths.sort()
+        }))
-            )
-
-            done()
-          })
-        })
       })
     })
   })
@@ -637,7 +608,7 @@ t.only().describe('watcher', function() {
   t.describe('parameters', function() {
     t.test('should throw error on non-existed file', function(done) {
       var somedir = builder.getPath('home/somedir')
-      watcher = watch(somedir)
+      watcher = new Watcher(somedir)
       watcher.on('error', done.finish(function(err) {
         assert.match(err.message, /not exist/)
       }))
@@ -645,7 +616,7 @@ t.only().describe('watcher', function() {
 
     t.test('should accept filename as Buffer', function(done) {
       var fpath = builder.getPath('home/a/file1')
-      watcher = watch(Buffer.from(fpath), { delay: 0 }, done.finish(function(evt, name) {
+      watcher = new Watcher(Buffer.from(fpath), { delay: 0 }, done.finish(function(evt, name) {
         assert.strictEqual(name, fpath)
       }))
       watcher.on('ready', function() {
@@ -667,7 +638,7 @@ t.only().describe('watcher', function() {
         builder.newFile(file1),
         builder.newFile(file2),
       ]).then(function() {
-        watcher = watch(fpaths, { delay: 0 }, function(evt, name) {
+        watcher = new Watcher(fpaths, { delay: 0 }, function(evt, name) {
           if (set.has(name)) {
             set.delete(name)
             counter.count()
@@ -696,9 +667,8 @@ t.only().describe('watcher', function() {
         builder.getPath(file2)
       ]
 
-      console.log()
       var changes = []
-      watcher = watch(fpaths, { delay: 100, recursive: true }, function(evt, name) {
+      watcher = new Watcher(fpaths, { delay: 100, recursive: true }, function(evt, name) {
         changes.push(name)
         counter.count()
       })
@@ -728,7 +698,7 @@ t.only().describe('watcher', function() {
       var file = 'home/a/file1'
       var fpath = builder.getPath(file)
 
-      watcher = watch(dir, { delay: 0 })
+      watcher = new Watcher(dir, { delay: 0 })
 
       watcher.on('change', done.finish(function(evt, name) {
         assert.strictEqual(evt, 'update')
@@ -736,7 +706,7 @@ t.only().describe('watcher', function() {
       }))
 
       watcher.on('ready', done.wrap(function() {
-        builder.modify(file)
+        builder.modify(file).catch(done)
       }))
     })
 
@@ -745,7 +715,7 @@ t.only().describe('watcher', function() {
         var dir = builder.getPath('home/a')
         var file = 'home/a/file1'
         var times = 0
-        watcher = watch(dir, { delay: 0 })
+        watcher = new Watcher(dir, { delay: 0 })
         watcher.on('change', function(evt, name) {
           times++
         })
@@ -766,76 +736,16 @@ t.only().describe('watcher', function() {
 
       t.test('should not watch after .close() is called', function(done) {
         var dir = builder.getPath('home')
-        watcher = watch(dir, { delay: 0, recursive: true })
+        watcher = new Watcher(dir, { delay: 0, recursive: true })
+
+        watcher.on('ready', function() {
           watcher.close()
+        })
 
-        watcher.getWatchedPaths(done.finish(function(dirs) {
+        watcher.on('close', done.finish(function(dirs) {
-          assert.strictEqual(dirs.length, 0)
+          assert.strictEqual(watcher.listeners.length, 0)
         }))
       })
     })
-
-    t.describe('getWatchedPaths()', function() {
-      t.test('should get all the watched paths', function(done) {
-        var home = builder.getPath('home')
-        watcher = watch(home, { delay: 0, recursive: true })
-
-        watcher.getWatchedPaths(function(paths) {
-          hasNativeRecursive(done.finish(function(supportRecursive) {
-            var watched = supportRecursive
-                // The home directory is the only one that's being watched
-                // if the recursive option is natively supported.
-              ? [home]
-                // Otherwise it should include all its subdirectories.
-              : builder.getAllDirectories()
-
-            assert.deepStrictEqual(
-              watched.sort(), paths.sort()
-            )
-          }))
-        })
-      })
-
-      t.test('should get its parent path instead of the file itself', function(done) {
-        var file = builder.getPath('home/a/file1')
-        // The parent path is actually being watched instead.
-        var parent = builder.getPath('home/a')
-
-        watcher = watch(file, { delay: 0 })
-
-        watcher.getWatchedPaths(done.finish(function(paths) {
-          assert.deepStrictEqual([parent], paths)
-        }))
-      })
-
-      t.test('should work correctly with composed watcher', function(done) {
-        var a = builder.getPath('home/a')
-
-        var b = builder.getPath('home/b')
-        var file = builder.getPath('home/b/file1')
-
-        var nested = builder.getPath('home/deep_node_modules')
-        var ma = builder.getPath('home/deep_node_modules/ma')
-        var mb = builder.getPath('home/deep_node_modules/mb')
-        var mc = builder.getPath('home/deep_node_modules/mc')
-
-        watcher = watch([a, file, nested], {
-          delay: 0,
-          recursive: true
-        })
-
-        watcher.getWatchedPaths(function(paths) {
-          hasNativeRecursive(done.finish(function(supportRecursive) {
-            var watched = supportRecursive
-              ? [a, b, nested]
-              : [a, b, nested, ma, mb, mc]
-
-            assert.deepStrictEqual(
-              watched.sort(), paths.sort()
-            )
-          }))
-        })
-      })
-    })
   })
 })

test/watch/builder.mjs

@@ -135,6 +135,8 @@ Builder.prototype.modify = function(fpath, delay) {
 Builder.prototype.remove = function(fpath) {
   let filePath = this.getPath(fpath)
   return fs.rm(filePath, { recursive: true, force: true })
+    .catch(() => this.delay(100))
+    .then(() => fs.rm(filePath, { recursive: true, force: true }))
 }
 
 Builder.prototype.removeSync = function(fpath) {