watcher: Imported node-watch into the project including tests.

.gitignore

@@ -102,3 +102,5 @@ dist
 
 # TernJS port file
 .tern-port
+
+test/watch/__TREE__

.npmrc

@@ -0,0 +1 @@
+package-lock=false

lib/eltro.d.ts

@@ -0,0 +1,47 @@
+declare interface Stats {
+  passed: number
+  failed: number
+  skipped: number
+}
+
+declare class Eltro {
+  __timeout: number
+  hasExclusive: boolean
+  reporter: 'dot' | 'list'
+  Eltro: Eltro
+  fileGroupMap: Map<string, Group>
+  groups: Array<Group>
+  activeGroup: Group | null
+  failedTests: Array<Test>
+  hasTests: boolean
+  starting: boolean
+  ignoreOnly: boolean
+  logger: null | { log: function(...param): void }
+  filename: string
+  prefix: string
+  temporary: { timeout: number, skip: boolean, only: boolean }
+  describeTemporary: { timeout: number, skip: boolean, only: boolean }
+
+  __runTest(stats: Stats, test: Test, prefix: string = 'Test', child?: Test | null = null)
+  __runGroup(group: Group, stats: Stats)
+  begin()
+  run()
+  setFilename(filename: string)
+  resetFilename(filename: string)
+
+  before(fn: (done?: Function) => void | Promise)
+  after(fn: (done?: Function) => void | Promise)
+  beforeEach(fn: (done?: Function) => void | Promise)
+  afterEach(fn: (done?: Function) => void | Promise)
+  describe(name: string, fn: Function)
+}
+
+declare class Test {
+
+}
+
+declare class Group {
+  
+}
+
+export default new Eltro()

lib/eltro.mjs

@@ -1,3 +1,4 @@
+/// <reference path="./eltro.d.ts"/>
 import * as readline from 'readline'
 import { runWithCallbackSafe } from './callback.mjs'
 import { printError } from './cli.mjs'
@@ -63,6 +64,13 @@ function Test(e, group, name, func) {
   this.name = name
   this.func = func
   this.error = null
+  this.startTime = null
+  this.totalTime = 0
+}
+
+Test.prototype.calculateTime = function() {
+  let end = process.hrtime(this.startTime)
+  this.totalTime = (end[0] * 1000 + Math.round(end[1] / 1000000))
 }
 
 Test.prototype.timeout = function(time) {
@@ -89,6 +97,25 @@ Test.prototype.clone = function(prefix = '') {
   return t
 }
 
+let stack = []
+function captureUnknownErrors(e) {
+  stack.push(e)
+}
+function cancelCaptureUnknown(e) {
+  stack.splice(stack.indexOf(e), 1)
+}
+
+process.on('uncaughtException', function(err) {
+  for (let i = stack.length - 1; i >= 0; i--) {
+    if (stack[i].captureOutsideExceptions) {
+      stack[i].captureOutsideExceptions(err)
+      return
+    }
+  }
+  console.error('-- UNCAUGHT EXCPEPTION OUTSIDE OF TEST RUNNER --')
+  console.error(err)
+})
+
 function Eltro() {
   this.__timeout = 2000
   this.hasExclusive = false
@@ -114,6 +141,7 @@ function Eltro() {
     skip: false,
     only: false
   }
+  this.captureOutsideExceptions = null
 }
 
 Eltro.prototype.begin = function() {
@@ -137,6 +165,7 @@ Eltro.prototype.__runTest = async function(stats, test, prefix = 'Test', child =
 
   if (!test.skipTest) {
     let err = await new Promise((resolve, reject) => {
+      this.captureOutsideExceptions = reject
       // Flag to check if we finished
       let finished = false
       let timeout = test.customTimeout || this.__timeout
@@ -144,6 +173,8 @@ Eltro.prototype.__runTest = async function(stats, test, prefix = 'Test', child =
       // Timeout timer in case test times out
       let timer = setTimeout(function() {
         if (finished === true) return
+
+        test.calculateTime()
         reject(new Error('timeout of ' + timeout + 'ms exceeded. Ensure the done() callback is being called in this test.'))
       }, timeout)
 
@@ -153,6 +184,7 @@ Eltro.prototype.__runTest = async function(stats, test, prefix = 'Test', child =
         let checkIsCallback = (test.func.toString()).match(/^(function)? *\([^\)]+\)/)
         let promise
 
+        test.startTime = process.hrtime()
         // If the test requires callback, wrap it in a promise where callback
         // either resolves or rejects that promise
         if (checkIsCallback) {
@@ -170,6 +202,7 @@ Eltro.prototype.__runTest = async function(stats, test, prefix = 'Test', child =
             // check if our test had already finished and if so, do nothing
             if (finished === true) return
 
+            test.calculateTime()
             finished = true
             clearTimeout(timer)
             resolve()
@@ -177,6 +210,7 @@ Eltro.prototype.__runTest = async function(stats, test, prefix = 'Test', child =
             // check if our test had already finished and if so, do nothing
             if (finished === true) return
 
+            test.calculateTime()
             finished = true
             clearTimeout(timer)
             reject(err)
@@ -185,6 +219,7 @@ Eltro.prototype.__runTest = async function(stats, test, prefix = 'Test', child =
           // check if our test had already finished and if so, do nothing
           if (finished === true) return
 
+          test.calculateTime()
           // Possible this was a synchronous test, pass immediately
           finished = true
           clearTimeout(timer)
@@ -194,6 +229,7 @@ Eltro.prototype.__runTest = async function(stats, test, prefix = 'Test', child =
         // check if our test had already finished and if so, do nothing
         if (finished === true) return
 
+        test.calculateTime()
         // An error occured while running function. Possible exception
         // during a synchronous test or something else.
         finished = true
@@ -232,15 +268,17 @@ Eltro.prototype.__runTest = async function(stats, test, prefix = 'Test', child =
     stats.skipped++
   }
 
+  this.captureOutsideExceptions = null
+
   if (this.reporter === 'list') {
     readline.clearLine(process.stdout, 0)
     readline.cursorTo(process.stdout, 0, null)
     if (markRealTest.skipTest) {
       process.stdout.write('    \x1b[94m- ' + markRealTest.name + '\x1b[0m\n')
     } else if (!markRealTest.error) {
-      process.stdout.write('    \x1b[32m√\x1b[90m ' + markRealTest.name + '\x1b[0m\n')
+      process.stdout.write('    \x1b[32m√\x1b[90m ' + markRealTest.name + ' (' + markRealTest.totalTime + 'ms)\x1b[0m\n')
     } else if (prefix === 'Test') {
-      process.stdout.write('    \x1b[31m' + this.failedTests.length + ') ' + markRealTest.name + '\x1b[0m\n')
+      process.stdout.write('    \x1b[31m' + this.failedTests.length + ') ' + markRealTest.name + ' (' + markRealTest.totalTime + 'ms)\x1b[0m\n')
     }
   } else if (this.reporter === 'dot') {
     if (markRealTest.skipTest) {
@@ -302,6 +340,8 @@ Eltro.prototype.run = async function() {
     console.log('')
   }
 
+  captureUnknownErrors(this)
+
   let stats = {
     passed: 0,
     failed: 0,
@@ -314,9 +354,10 @@ Eltro.prototype.run = async function() {
       await this.__runGroup(this.groups[i], stats)
     }
   }
-
   let end = process.hrtime(start)
 
+  cancelCaptureUnknown(this)
+
   if (this.reporter === 'test') {
     if (this.logger && this.logger.log) {
       if (this.failedTests.length) {

lib/watch/LICENSE

@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2012-2021 Yuan Chuan <yuanchuan23@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

lib/watch/has-native-recursive.mjs

@@ -0,0 +1,114 @@
+import fs from 'fs'
+import os from 'os'
+import path from 'path'
+import * as is from './is.mjs'
+
+let IS_SUPPORT
+let TEMP_DIR = os.tmpdir && os.tmpdir()
+  || process.env.TMPDIR
+  || process.env.TEMP
+  || process.cwd()
+
+function TempStack() {
+  this.stack = []
+}
+
+
+TempStack.prototype.create = function(type, base) {
+  let name = path.join(base,
+    'node-watch-' + Math.random().toString(16).substr(2)
+  )
+  this.stack.push({ name: name, type: type })
+  return name
+}
+TempStack.prototype.write = function(/* file */) {
+  for (let i = 0; i < arguments.length; ++i) {
+    fs.writeFileSync(arguments[i], ' ')
+  }
+}
+TempStack.prototype.mkdir = function(/* dirs */) {
+  for (let i = 0; i < arguments.length; ++i) {
+    fs.mkdirSync(arguments[i])
+  }
+}
+TempStack.prototype.cleanup = function(fn) {
+  try {
+    let temp
+    while ((temp = this.stack.pop())) {
+      let type = temp.type
+      let name = temp.name
+      if (type === 'file' && is.file(name)) {
+        fs.unlinkSync(name)
+      }
+      else if (type === 'dir' && is.directory(name)) {
+        fs.rmdirSync(name)
+      }
+    }
+  }
+  finally {
+    if (is.func(fn)) fn()
+  }
+}
+
+let pending = false
+
+export default function hasNativeRecursive(fn) {
+  if (!is.func(fn)) {
+    return false
+  }
+  if (IS_SUPPORT !== undefined) {
+    return fn(IS_SUPPORT)
+  }
+
+  if (!pending) {
+    pending = true
+  }
+  // check again later
+  else {
+    return setTimeout(function() {
+      hasNativeRecursive(fn)
+    }, 300)
+  }
+
+  let stack = new TempStack()
+  let parent = stack.create('dir', TEMP_DIR)
+  let child = stack.create('dir', parent)
+  let file = stack.create('file', child)
+
+  stack.mkdir(parent, child)
+
+  let options = { recursive: true }
+  let watcher
+
+  try {
+    watcher = fs.watch(parent, options)
+  } catch (e) {
+    if (e.code == 'ERR_FEATURE_UNAVAILABLE_ON_PLATFORM') {
+      return fn(IS_SUPPORT = false)
+    } else {
+      throw e
+    }
+  }
+
+  if (!watcher) {
+    return false
+  }
+
+  let timer = setTimeout(function() {
+    watcher.close()
+    stack.cleanup(function() {
+      fn(IS_SUPPORT = false)
+    })
+  }, 200)
+
+  watcher.on('change', function(evt, name) {
+    if (path.basename(file) === path.basename(name)) {
+      watcher.close()
+      clearTimeout(timer)
+      stack.cleanup(function() {
+        fn(IS_SUPPORT = true)
+      })
+    }
+  })
+  stack.write(file)
+}

lib/watch/index.mjs

@@ -0,0 +1,549 @@
+import fs from 'fs'
+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 SKIP_FLAG = Symbol('skip');
+
+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) {
+    return self.indexOf(v) === i;
+  });
+}
+
+// One level flat
+function flat1(arr) {
+  return arr.reduce(function(acc, v) {
+    return acc.concat(v);
+  }, []);
+}
+
+function assertEncoding(encoding) {
+  if (encoding && encoding !== 'buffer' && !Buffer.isEncoding(encoding)) {
+    throw new Error('Unknown encoding: ' + encoding);
+  }
+}
+
+function guard(fn) {
+  if (is.func(fn)) {
+    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) {
+  return names.map(function(n) {
+    return is.exists(n)
+      ? [EVENT_UPDATE, n]
+      : [EVENT_REMOVE, n];
+  });
+}
+
+function getMessages(cache) {
+  var filtered = unique(cache);
+
+  // Saving file from an editor? If so, assuming the
+  // 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) {
+    var dup = hasDup(cache.map(function(c) {
+      return c.replace(reg, '');
+    }));
+    if (dup) {
+      filtered = filtered.filter(function(m) {
+        return is.exists(m);
+      });
+    }
+  }
+
+  return composeMessage(filtered);
+}
+
+function debounce(info, fn) {
+  var timer, cache = [];
+  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() {
+  var memo = {};
+  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) {
+  try {
+    return fs.watch(dir, opts);
+  } catch (e) {
+    process.nextTick(function() {
+      watcher.emit('error', e);
+    });
+  }
+}
+
+function getSubDirectories(dir, fn, done = function() {}) {
+  if (is.directory(dir)) {
+    fs.readdir(dir, function(err, all) {
+      if (err) {
+        // don't throw permission errors.
+        if (/^(EPERM|EACCES)$/.test(err.code)) {
+          console.warn('Warning: Cannot access %s.', dir);
+        } else {
+          throw err;
+        }
+      }
+      else {
+        all.forEach(function(f) {
+          var sdir = path.join(dir, f);
+          if (is.directory(sdir)) fn(sdir);
+        });
+        done();
+      }
+    });
+  } else {
+    done();
+  }
+}
+
+function semaphore(final) {
+  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
+    var name = rawName;
+    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 && '');
+      self.flag = 'windows-error';
+      self.close(watcherPath);
+    } else {
+      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, {
+    type: 'file',
+    fpath: parent,
+    options: Object.assign({}, opts, {
+      encoding: options.encoding
+    }),
+    compareName: function(n) {
+      return is.samePath(n, file);
+    }
+  });
+
+  if (is.func(fn)) {
+    if (fn.length === 1) deprecationWarning();
+    this.on('change', fn);
+  }
+}
+
+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();
+}

lib/watch/is.mjs

@@ -0,0 +1,74 @@
+import fs from 'fs'
+import path from 'path'
+import os from 'os'
+
+function matchObject(item, str) {
+  return Object.prototype.toString.call(item)
+    === '[object ' + str + ']'
+}
+
+function checkStat(name, fn) {
+  try {
+    return fn(name)
+  } catch (err) {
+    if (/^(ENOENT|EPERM|EACCES)$/.test(err.code)) {
+      if (err.code !== 'ENOENT') {
+        console.warn('Warning: Cannot access %s', name)
+      }
+      return false
+    }
+    throw err
+  }
+}
+
+export function nil(item) {
+  return item == null
+}
+export function array(item) {
+  return Array.isArray(item)
+}
+export function emptyObject(item) {
+  for (var key in item) {
+    return false
+  }
+  return true
+}
+export function buffer(item) {
+  return Buffer.isBuffer(item)
+}
+export function regExp(item) {
+  return matchObject(item, 'RegExp')
+}
+export function string(item) {
+  return matchObject(item, 'String')
+}
+export function func(item) {
+  return typeof item === 'function'
+}
+export function number(item) {
+  return matchObject(item, 'Number')
+}
+export function exists(name) {
+  return fs.existsSync(name)
+}
+export function file(name) {
+  return checkStat(name, function(n) {
+    return fs.statSync(n).isFile()
+  })
+}
+export function samePath(a, b) {
+  return path.resolve(a) === path.resolve(b)
+}
+export function directory(name) {
+  return checkStat(name, function(n) {
+  return fs.statSync(n).isDirectory()
+  })
+}
+export function symbolicLink(name) {
+  return checkStat(name, function(n) {
+  return fs.lstatSync(n).isSymbolicLink()
+  })
+}
+export function windows() {
+  return os.platform() === 'win32'
+}

package.json

@@ -4,7 +4,7 @@
   "description": "Eltro is a tiny no-dependancy test framework for node",
   "main": "index.mjs",
   "scripts": {
-    "test": "node cli.mjs test/**/*.test.mjs",
+    "test": "node cli.mjs 'test/**/*.test.mjs'",
     "test:watch": "npm-watch test"
   },
   "watch": {

test/cli.test.mjs

@@ -124,7 +124,7 @@ t.describe('CLI', function() {
 
   t.describe('#processTargets()', function() {
     t.test('should mark errored if empty', async function() {
-      cli.targets = ['test/folder1/*.txt']
+      cli.targets = ['test/testtree/folder1/*.txt']
       await cli.processTargets()
     
       assert.strictEqual(cli.files.length, 0)
@@ -132,31 +132,31 @@ t.describe('CLI', function() {
     })
 
     t.test('should support direct file path if exists', async function() {
-      cli.targets = ['test/folder1/sampletest1.temp.mjs']
+      cli.targets = ['test/testtree/folder1/sampletest1.temp.mjs']
       await cli.processTargets()
     
       assert.strictEqual(cli.files.length, 1)
-      assert.strictEqual(cli.files[0], 'test/folder1/sampletest1.temp.mjs')
+      assert.strictEqual(cli.files[0], 'test/testtree/folder1/sampletest1.temp.mjs')
     })
     
     t.test('should return all files in a directory', async function() {
-      cli.targets = ['test/folder1/']
+      cli.targets = ['test/testtree/folder1/']
       await cli.processTargets()
     
       assert.strictEqual(cli.files.length, 2)
       cli.files.sort()
-      assert.strictEqual(cli.files[0], 'test/folder1/sampletest1.temp.mjs')
-      assert.strictEqual(cli.files[1], 'test/folder1/sampletest2.temp.mjs')
+      assert.strictEqual(cli.files[0], 'test/testtree/folder1/sampletest1.temp.mjs')
+      assert.strictEqual(cli.files[1], 'test/testtree/folder1/sampletest2.temp.mjs')
     })
     
     t.test('should support start as folder substitute', async function() {
-      cli.targets = ['*/folder1/']
+      cli.targets = ['*/testtree/folder1/']
       await cli.processTargets()
     
       assert.strictEqual(cli.files.length, 2)
       cli.files.sort()
-      assert.strictEqual(cli.files[0], 'test/folder1/sampletest1.temp.mjs')
-      assert.strictEqual(cli.files[1], 'test/folder1/sampletest2.temp.mjs')
+      assert.strictEqual(cli.files[0], 'test/testtree/folder1/sampletest1.temp.mjs')
+      assert.strictEqual(cli.files[1], 'test/testtree/folder1/sampletest2.temp.mjs')
     })
     
     t.test('should support grabbing only files in folder', async function() {
@@ -182,28 +182,28 @@ t.describe('CLI', function() {
     })
     
     t.test('should support multiple star pattern', async function() {
-      cli.targets = ['test/*/*.mjs']
+      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/folder1/sampletest1.temp.mjs',
-        'test/folder1/sampletest2.temp.mjs',
-        'test/folder2/sampletest3.temp.mjs',
-        'test/folder2/sampletest4.temp.mjs',
+        'test/testtree/folder1/sampletest1.temp.mjs',
+        'test/testtree/folder1/sampletest2.temp.mjs',
+        'test/testtree/folder2/sampletest3.temp.mjs',
+        'test/testtree/folder2/sampletest4.temp.mjs',
       ])
     
-      cli.targets = ['test/*/sampletest*.mjs']
+      cli.targets = ['test/testtree/*/sampletest*.mjs']
       await cli.processTargets()
-    
       assert.strictEqual(cli.files.length, 4)
       cli.files.sort()
       assert.deepEqual(cli.files, [
-        'test/folder1/sampletest1.temp.mjs',
-        'test/folder1/sampletest2.temp.mjs',
-        'test/folder2/sampletest3.temp.mjs',
-        'test/folder2/sampletest4.temp.mjs',
+        'test/testtree/folder1/sampletest1.temp.mjs',
+        'test/testtree/folder1/sampletest2.temp.mjs',
+        'test/testtree/folder2/sampletest3.temp.mjs',
+        'test/testtree/folder2/sampletest4.temp.mjs',
       ])
     })
     
@@ -223,11 +223,11 @@ t.describe('CLI', function() {
       }
     
       for (let i = 0; i < cli.files.length; i++) {
-        found.sampletest1 = found.sampletest1 || cli.files[i] === 'test/folder1/sampletest1.temp.mjs'
-        found.sampletest2 = found.sampletest2 || cli.files[i] === 'test/folder1/sampletest2.temp.mjs'
-        found.sampletest3 = found.sampletest3 || cli.files[i] === 'test/folder2/sampletest3.temp.mjs'
-        found.sampletest4 = found.sampletest4 || cli.files[i] === 'test/folder2/sampletest4.temp.mjs'
-        found.sampletest5 = found.sampletest5 || cli.files[i] === 'test/folder2/sampletest5.temp.txt'
+        found.sampletest1 = found.sampletest1 || cli.files[i] === 'test/testtree/folder1/sampletest1.temp.mjs'
+        found.sampletest2 = found.sampletest2 || cli.files[i] === 'test/testtree/folder1/sampletest2.temp.mjs'
+        found.sampletest3 = found.sampletest3 || cli.files[i] === 'test/testtree/folder2/sampletest3.temp.mjs'
+        found.sampletest4 = found.sampletest4 || cli.files[i] === 'test/testtree/folder2/sampletest4.temp.mjs'
+        found.sampletest5 = found.sampletest5 || cli.files[i] === 'test/testtree/folder2/sampletest5.temp.txt'
         found.cli = found.cli || cli.files[i] === 'test/cli.test.mjs'
       }
     
@@ -257,11 +257,11 @@ t.describe('CLI', function() {
       }
     
       for (let i = 0; i < cli.files.length; i++) {
-        found.sampletest1 = found.sampletest1 || cli.files[i] === 'test/folder1/sampletest1.temp.mjs'
-        found.sampletest2 = found.sampletest2 || cli.files[i] === 'test/folder1/sampletest2.temp.mjs'
-        found.sampletest3 = found.sampletest3 || cli.files[i] === 'test/folder2/sampletest3.temp.mjs'
-        found.sampletest4 = found.sampletest4 || cli.files[i] === 'test/folder2/sampletest4.temp.mjs'
-        found.sampletest5 = found.sampletest5 || cli.files[i] === 'test/folder2/sampletest5.temp.txt'
+        found.sampletest1 = found.sampletest1 || cli.files[i] === 'test/testtree/folder1/sampletest1.temp.mjs'
+        found.sampletest2 = found.sampletest2 || cli.files[i] === 'test/testtree/folder1/sampletest2.temp.mjs'
+        found.sampletest3 = found.sampletest3 || cli.files[i] === 'test/testtree/folder2/sampletest3.temp.mjs'
+        found.sampletest4 = found.sampletest4 || cli.files[i] === 'test/testtree/folder2/sampletest4.temp.mjs'
+        found.sampletest5 = found.sampletest5 || cli.files[i] === 'test/testtree/folder2/sampletest5.temp.txt'
         found.cli = found.cli || cli.files[i] === 'test/cli.test.mjs'
       }
     

test/eltro.test.mjs

@@ -226,6 +226,24 @@ e.test('Eltro should support callback rejected errors', async function() {
   assert.strictEqual(t.failedTests[0].error, assertError)
 })
 
+e.test('Eltro should support capturing unknown errors outside scope', async function() {
+  testsWereRun = true
+  const assertError = new Error()
+  const t = CreateT()
+  t.begin()
+  t.describe('', function() {
+    t.test('', function(cb) {
+      process.nextTick(function() {
+        console.log('throw')
+        throw assertError
+      })
+    })
+  })
+  await t.run()
+  assert.strictEqual(t.failedTests.length, 1)
+  assert.strictEqual(t.failedTests[0].error, assertError)
+})
+
 e.test('Eltro should support timing out tests', async function() {
   testsWereRun = true
   const t = CreateT()

test/watch.test.mjs

@@ -0,0 +1,862 @@
+import path from 'path'
+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 * as is from '../lib/watch/is.mjs'
+import hasNativeRecursive from '../lib/watch/has-native-recursive.mjs'
+
+const builder = new Builder()
+let watcher
+
+function htTimeToMs(end) {
+  return end[0] * 1000 + Math.round(end[1] / 1000000)
+}
+
+t.before(function() {
+  return builder.init()
+})
+
+t.afterEach(function(done) {
+  if (watcher && !watcher.isClosed()) {
+    watcher.on('close', done)
+    watcher.close()
+  } else {
+    done()
+  }
+})
+
+t.after(function() {
+  if (builder) {
+    builder.cleanup()
+  }
+})
+
+function wait(fn, timeout) {
+  try {
+    fn()
+  } catch (error) {
+    timeout -= 30
+    if (timeout >= 0) {
+      setTimeout(function() {
+        wait(fn, timeout)
+      }, 30)
+    } else {
+      throw error
+    }
+  }
+}
+
+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.on('close', done)
+    watcher.close()
+  })
+
+  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.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.on('ready', done)
+  })
+
+  t.test('should emit `ready` properly in a composed watcher', function(done) {
+    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.on('ready', done)
+  })
+})
+
+t.describe('watch for files', function() {
+  t.test('should watch a single file and keep watching', function(done) {
+    var counter = new Counter(done, 3)
+    var file = 'home/a/file1'
+    var fpath = builder.getPath(file)
+    watcher = watch(fpath, { delay: 0 }, function(evt, name) {
+      assert.strictEqual(fpath, name)
+      counter.count()
+    })
+    watcher.on('ready', function() {
+      counter.waitForCount(builder.modify(file))
+        .then(() => counter.waitForCount(builder.modify(file)))
+        .then(() => counter.waitForCount(builder.modify(file)))
+    })
+  })
+
+  t.test('should watch files inside a directory', function(done) {
+    var fpath = builder.getPath('home/a')
+    var set = new Set()
+    set.add(builder.getPath('home/a/file1'))
+    set.add(builder.getPath('home/a/file2'))
+
+    Promise.all([
+      builder.newFile('home/a/file1'),
+      builder.newFile('home/a/file2'),
+    ]).then(() => {
+      watcher = watch(fpath, { delay: 0 }, function(evt, name) {
+        set.delete(name)
+        if (!set.size) {
+          done()
+        }
+      })
+  
+      watcher.on('ready', function() {
+        Promise.all([
+          builder.modify('home/a/file1'),
+          builder.modify('home/a/file2'),
+        ]).then()
+      })
+    })
+  })
+
+  t.test('should debounce multiple triggers', function(done) {
+    var counter = new Counter()
+    var file = 'home/a/file2'
+    var fpath = builder.getPath(file)
+
+    var start = process.hrtime()
+    var middle = start
+    var end = start
+    
+    watcher = watch(fpath, { delay: 100 }, function(evt, name) {
+      if (fpath === name) counter.count()
+    })
+
+    watcher.on('ready', function() {
+      builder.modify(file)
+        .then(() => builder.modify(file))
+        .then(() => builder.modify(file))
+        .then(() => {
+          middle = htTimeToMs(process.hrtime(start))
+          return counter.waitForCount()
+        })
+        .then(() => {
+          assert.strictEqual(counter.counter, 1)
+          end = htTimeToMs(process.hrtime(start))
+
+          assert.ok(end - middle > 50)
+          assert.ok(end >= 100)
+          done()
+        })
+        .catch(done)
+    })
+  })
+
+  t.test('should listen to new created files', function(done) {
+    var home = builder.getPath('home')
+    var counter = new Counter()
+    var newfile1 = 'home/a/newfile' + builder.randomName()
+    var newfile2 = 'home/a/newfile' + builder.randomName()
+    var set = new Set([
+      builder.getPath(newfile1),
+      builder.getPath(newfile2),
+    ])
+    var changes = []
+    var extra = []
+    watcher = watch(home, { delay: 0, recursive: true }, function(evt, name) {
+      if (set.has(name)) {
+        changes.push(name)
+        counter.count()
+      } else {
+        extra.push(name)
+      }
+    })
+    watcher.on('ready', function() {
+      counter.waitForCount(builder.newFile(newfile1))
+        .then(() => counter.waitForCount(builder.newFile(newfile2)))
+        .then(() => {
+          assert.deepStrictEqual(changes, [...set.values()])
+          assert.deepStrictEqual(extra, [])
+          done()
+        })
+        .catch(done)
+    })
+  })
+
+  t.test('should error when parent gets deleted before calling fs.watch', function(done) {
+    var fpath = builder.getPath('home/a/file1')
+    builder.newFile('home/a/file1')
+      .then(() => {
+        watcher = watch(fpath, Object.defineProperty({}, 'test', {
+          enumerable: true,
+          get: function() {
+            builder.removeSync('home/a')
+            return 'test'
+          }
+        }))
+        watcher.on('error', function() {
+          done()
+        })
+      })
+  })
+})
+
+t.describe('watch for directories', function() {
+  t.test('should watch directories inside a directory', function(done) {
+    var home = builder.getPath('home')
+    var dir = builder.getPath('home/c')
+
+    builder.createDirectory(dir).then(() => {
+      watcher = watch(home, { delay: 0, recursive: true }, function(evt, name) {
+        if (name === dir && evt === 'remove') {
+          done()
+        }
+      })
+      watcher.on('ready', function() {
+        builder.remove('home/c').then()
+      })
+    })
+  })
+
+  t.test('should watch new created directories', function(done) {
+    var home = builder.getPath('home')
+
+    builder.remove('home/new').then(() => {
+      watcher = watch(home, { delay: 0, recursive: true }, function(evt, name) {
+        if (name === builder.getPath('home/new/file1')) {
+          done()
+        }
+      })
+      watcher.on('ready', function() {
+        builder.newFile('home/new/file1')
+          .then(() => builder.modify('home/new/file1'))
+          .catch(done)
+      })
+    })
+  })
+
+  t.test('should not watch new created directories which are being skipped in the filter', function(done) {
+    var counter = new Counter()
+    var home = builder.getPath('home')
+
+    var options = {
+      delay: 0,
+      recursive: true,
+      filter: function(filePath, SKIP_FLAG) {
+        if (/ignored/.test(filePath)) {
+          counter.count()
+          return SKIP_FLAG
+        }
+        return false
+      }
+    }
+
+    builder.remove('home/ignored/file').then(() => {
+      watcher = watch(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')
+          .then(() => {
+            assert.ok(counter.counter)
+            done()
+          })
+          .catch(done)
+      })
+    })
+  })
+
+  t.test('should keep watching after removal of sub directory', function(done) {
+    var counter = new Counter(done, 3)
+    var home = builder.getPath('home')
+    var file1 = builder.getPath('home/e/file1')
+    var file2 = builder.getPath('home/e/file2')
+    var dir = builder.getPath('home/e/sub')
+    var set = new Set()
+
+    Promise.all([
+      builder.newFile('home/e/sub/testfile'),
+      builder.newFile('home/e/file1'),
+      builder.newFile('home/e/file2'),
+    ]).then(() => {
+
+      watcher = watch(home, { delay: 0, recursive: true }, function(evt, name) {
+        if (name === dir || name === file1 || name === file2) {
+          if (!set.has(name)) {
+            set.add(name)
+            counter.count()
+          }
+        }
+      })
+
+      watcher.on('ready', function() {
+        builder.remove('home/e/sub')
+        builder.modify('home/e/file1')
+        builder.modify('home/e/file2')
+      })
+    })
+  })
+
+  t.test('should watch new directories without delay', function(done) {
+    var counter = new Counter(done, 1)
+    var home = builder.getPath('home')
+
+    builder.remove('home/new').then(() => {
+      watcher = watch(home, { delay: 200, recursive: true }, function(evt, name) {
+        if (name === builder.getPath('home/new/file1')) {
+          counter.count()
+        }
+      })
+      watcher.on('ready', function() {
+        builder.newFile('home/new/file1')
+          .then(() => builder.modify('home/new/file1'))
+          .then(() => builder.modify('home/new/file1'))
+      })
+    })
+  })
+
+  t.test('should error when directory gets deleted before calling fs.watch', function(done) {
+    var dir = 'home/c'
+    var fpath = builder.getPath(dir)
+
+    builder.createDirectory(dir).then(() => {
+      watcher = watch(fpath, Object.defineProperty({}, 'test', {
+        enumerable: true,
+        get: function() {
+          builder.removeSync(dir)
+          return 'test'
+        }
+      }))
+      watcher.on('error', function() {
+        done()
+      })
+    })
+  })
+})
+
+t.describe('file events', function() {
+  var file = 'home/a/file1'
+  var fpath = builder.getPath(file)
+
+  t.beforeEach(function() {
+    return builder.newFile(file)
+  })
+
+  t.test('should identify `remove` event', function(done) {
+    watcher = watch(fpath, { delay: 0 }, function(evt, name) {
+      if (evt === 'remove' && name === fpath) {
+        done()
+      }
+    })
+    watcher.on('ready', function() {
+      builder.remove(file).catch(done)
+    })
+  })
+
+  t.test('should identify `remove` event on directory', function(done) {
+    var dir = 'home/a'
+    var home = builder.getPath('home')
+    var fpath = builder.getPath(dir)
+
+    watcher = watch(home, { delay: 0 }, function(evt, name) {
+      if (evt === 'remove' && name === fpath) done()
+    })
+    watcher.on('ready', function() {
+      builder.remove(dir).catch(done)
+    })
+  })
+
+  t.test('should be able to handle many events on deleting', function(done) {
+    var dir = 'home/a'
+    var fpath = builder.getPath(dir)
+  
+    builder.newRandomFiles(dir, 100).then(names => {
+      var counter = new Counter(done, names.length)
+
+      watcher = watch(fpath, { delay: 10 }, function(evt, name) {
+        if (evt === 'remove') counter.count()
+      })
+
+      watcher.on('ready', function() {
+        Promise.all(names.map(x => builder.remove(path.join(dir, x)))).catch(done)
+      })
+    })
+  })
+
+  t.test('should identify `update` event', function(done) {
+    var file = 'home/b/file1'
+    var fpath = builder.getPath(file)
+    builder.newFile(fpath).then(() => {
+      watcher = watch(fpath, { delay: 0 }, function(evt, name) {
+        if (evt === 'update' && name === fpath) done()
+      })
+      watcher.on('ready', function() {
+        builder.modify(file).catch(done)
+      })
+    })
+  })
+
+  t.test('should report `update` on new files', function(done) {
+    var dir = builder.getPath('home/a')
+    var file = 'home/a/newfile_' + builder.randomName()
+    var fpath = builder.getPath(file)
+
+    watcher = watch(dir, { delay: 0 }, function(evt, name) {
+      if (evt === 'update' && name === fpath) done()
+    })
+    watcher.on('ready', function() {
+      builder.newFile(file).catch(done)
+    })
+  })
+})
+
+t.describe('options', function() {
+  t.describe('recursive', 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) {
+        if (file === name) {
+          done()
+        }
+      })
+      watcher.on('ready', function() {
+        builder.modify('home/bb/file1').catch(done)
+      })
+    })
+  })
+
+  t.describe('encoding', function() {
+    let options = {
+      delay: 0,
+      encoding: 'unknown'
+    };
+
+    var dir = 'home/a'
+    var fdir = builder.getPath('home/a')
+    var file = 'home/a/file1'
+    var fpath = builder.getPath(file)
+
+    t.before(() => {
+      return builder.newFile(file)
+    })
+
+    t.test('should throw on invalid encoding', function(done) {
+      options.encoding = 'unknown'
+      try {
+        watcher = watch(fdir, options)
+      } catch (e) {
+        done()
+      }
+    })
+
+    t.test('should accept an encoding string', function(done) {
+      options.encoding = 'utf8'
+      watcher = watch(fdir, options, done.finish(function(evt, name) {
+        assert.strictEqual(name.toString(), fpath)
+      }))
+      watcher.on('ready', function() {
+        builder.modify(file).catch(done)
+      })
+    })
+
+    t.test('should support buffer encoding', function(done) {
+      options.encoding = 'buffer'
+      watcher = watch(fdir, options, done.finish(function(evt, name) {
+        assert.ok(Buffer.isBuffer(name), 'not a Buffer')
+        assert.strictEqual(name.toString(), fpath)
+      }))
+
+      watcher.on('ready', function() {
+        builder.modify(file).catch(done)
+      })
+    })
+
+    t.test('should support base64 encoding', function(done) {
+      options.encoding = 'base64'
+      watcher = watch(fdir, options, done.finish(function(evt, name) {
+        assert.strictEqual(
+          name,
+          Buffer.from(fpath).toString('base64'),
+          'wrong base64 encoding'
+        )
+      }))
+      watcher.on('ready', function() {
+        builder.modify(file).catch(done)
+      })
+    })
+
+    t.test('should support hex encoding', function(done) {
+      options.encoding = 'hex'
+      watcher = watch(fdir, options, done.finish(function(evt, name) {
+        assert.strictEqual(
+          name,
+          Buffer.from(fpath).toString('hex'),
+          'wrong hex encoding'
+        )
+      }))
+      watcher.on('ready', function() {
+        builder.modify(file).catch(done)
+      })
+    })
+  })
+
+  t.describe('filter', function() {
+    t.test('should only watch filtered directories', function(done) {
+      var matchRegularDir = false
+      var matchIgnoredDir = false
+      var counter = new Counter(done.finish(function() {
+        assert(matchRegularDir, 'watch failed to detect regular file')
+        assert(!matchIgnoredDir, 'fail to ignore path `deep_node_modules`')
+      }), 1, true)
+
+      var options = {
+        delay: 0,
+        recursive: true,
+        filter: function(name) {
+          return !/deep_node_modules/.test(name)
+        }
+      }
+
+      watcher = watch(builder.getPath('home'), options, function(evt, name) {
+        if (/deep_node_modules/.test(name)) {
+          matchIgnoredDir = true
+        } else {
+          matchRegularDir = true
+        }
+        counter.count()
+      })
+      watcher.on('ready', function() {
+        counter.startCounting()
+        builder.modify('home/deep_node_modules/ma/file1')
+          .then(() => builder.modify('home/b/file1'))
+          .catch(done)
+      })
+    })
+
+    t.test('should only report filtered files', function(done) {
+      var dir = builder.getPath('home')
+      var file1 = 'home/bb/file1'
+      var file2 = 'home/bb/file2'
+
+
+      var counter = new Counter(done.finish(function() {
+        assert.strictEqual(matchIgnoredFile, false, 'home/bb/file1 should be ignored')
+      }), 1, true)
+
+      var options = {
+        delay: 0,
+        recursive: true,
+        filter: function(name) {
+          return /file2/.test(name)
+        }
+      }
+
+      var times = 0
+      var matchIgnoredFile = false
+      watcher = watch(dir, options, function(evt, name) {
+        if (name === builder.getPath(file1)) {
+          matchIgnoredFile = true
+        }
+        counter.count()
+      })
+      watcher.on('ready', function() {
+        counter.startCounting()
+
+        builder.modify(file2)
+          .then(() => builder.modify(file1))
+          .catch(done)
+      })
+    })
+
+    t.test('should be able to filter directly with regexp', function(done) {
+      var dir = builder.getPath('home')
+      var file1 = 'home/bb/file1'
+      var file2 = 'home/bb/file2'
+
+
+      var counter = new Counter(done.finish(function() {
+        assert.strictEqual(matchIgnoredFile, false, 'home/bb/file1 should be ignored')
+      }), 1, true)
+
+      var options = {
+        delay: 0,
+        recursive: true,
+        filter: /file2/
+      }
+
+      var times = 0
+      var matchIgnoredFile = false
+      watcher = watch(dir, options, function(evt, name) {
+        if (name === builder.getPath(file1)) {
+          matchIgnoredFile = true
+        }
+        counter.count()
+      })
+      watcher.on('ready', function() {
+        counter.startCounting()
+
+        builder.modify(file2)
+          .then(() => builder.modify(file1))
+          .catch(done)
+      })
+    })
+
+    t.test('should be able to skip subdirectories with `skip` flag', function(done) {
+      var home = builder.getPath('home')
+      var options = {
+        delay: 0,
+        recursive: true,
+        filter: function(name, skip) {
+          if (/\/deep_node_modules/.test(name)) return skip
+        }
+      }
+      watcher = watch(home, options)
+
+      watcher.getWatchedPaths(function(paths) {
+        hasNativeRecursive(function(supportRecursive) {
+          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)
+              })
+
+          assert.deepStrictEqual(
+            watched.sort(), paths.sort()
+          )
+
+          done()
+        })
+      })
+    })
+  })
+})
+
+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.on('error', done.finish(function(err) {
+      assert.match(err.message, /not exist/)
+    }))
+  })
+
+  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) {
+      assert.strictEqual(name, fpath)
+    }))
+    watcher.on('ready', function() {
+      builder.modify('home/a/file1').catch(done)
+    })
+  })
+
+  t.test('should compose array of files or directories', function(done) {
+    var counter = new Counter(done, 2)
+    var file1 = 'home/a/file1'
+    var file2 = 'home/a/file2'
+    var fpaths = [
+      builder.getPath(file1),
+      builder.getPath(file2)
+    ]
+
+    var times = 0
+    watcher = watch(fpaths, { delay: 0 }, function(evt, name) {
+      if (fpaths.indexOf(name) !== -1) counter.count()
+    })
+
+    watcher.on('ready', function() {
+      Promise.all([
+        builder.modify(file1),
+        builder.modify(file2),
+      ]).catch(done)
+    })
+  })
+
+  t.test('should filter duplicate events for composed watcher', function(done) {
+    var home = 'home'
+    var dir = 'home/a'
+    var file1 = 'home/a/file1'
+    var file2 = 'home/a/file2'
+    var fpaths = [
+      builder.getPath(home),
+      builder.getPath(dir),
+      builder.getPath(file1),
+      builder.getPath(file2)
+    ]
+
+    var changes = []
+    watcher = watch(fpaths, { delay: 100, recursive: true }, function(evt, name) {
+      changes.push(name)
+    })
+
+    watcher.on('ready', function() {
+      builder.modify(file1)
+      builder.modify(file2, 50)
+
+      wait(function() {
+        assert.deepStrictEqual(
+          changes,
+          [builder.getPath(file1), builder.getPath(file2)]
+        )
+        done()
+      }, 200)
+    })
+  })
+})
+
+t.describe('watcher object', function() {
+  t.test('should using watcher object to watch', function(done) {
+    var dir = builder.getPath('home/a')
+    var file = 'home/a/file1'
+    var fpath = builder.getPath(file)
+
+    watcher = watch(dir, { delay: 0 })
+    watcher.on('ready', function() {
+      watcher.on('change', function(evt, name) {
+        assert.strictEqual(evt, 'update')
+        assert.strictEqual(name, fpath)
+        done()
+      })
+      builder.modify(file)
+    })
+  })
+
+  t.describe('close()', function() {
+    t.test('should close a watcher using .close()', function(done) {
+      var dir = builder.getPath('home/a')
+      var file = 'home/a/file1'
+      var times = 0
+      watcher = watch(dir, { delay: 0 })
+      watcher.on('change', function(evt, name) {
+        times++
+      })
+      watcher.on('ready', function() {
+
+        watcher.close()
+
+        builder.modify(file)
+        builder.modify(file, 100)
+
+        wait(function() {
+          assert(watcher.isClosed(), 'watcher should be closed')
+          assert.strictEqual(times, 0, 'failed to close the watcher')
+          done()
+        }, 150)
+      })
+    })
+
+    t.test('should not watch after .close() is called', function(done) {
+      var dir = builder.getPath('home')
+      watcher = watch(dir, { delay: 0, recursive: true })
+      watcher.close()
+
+      watcher.getWatchedPaths(function(dirs) {
+        assert(dirs.length === 0)
+        done()
+      })
+    })
+
+    t.test('Do not emit after close', function(done) {
+      var dir = builder.getPath('home/a')
+      var file = 'home/a/file1'
+      var times = 0
+      watcher = watch(dir, { delay: 0 })
+      watcher.on('change', function(evt, name) {
+        times++
+      })
+      watcher.on('ready', function() {
+
+        watcher.close()
+
+        var timer = setInterval(function() {
+          builder.modify(file)
+        })
+
+        wait(function() {
+          clearInterval(timer)
+          assert(watcher.isClosed(), 'watcher should be closed')
+          assert.strictEqual(times, 0, 'failed to close the watcher')
+          done()
+        }, 100)
+      })
+    })
+
+  })
+
+  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(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()
+          )
+
+          done()
+        })
+      })
+    })
+
+    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(function(paths) {
+        assert.deepStrictEqual([parent], paths)
+        done()
+      })
+    })
+
+    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(function(supportRecursive) {
+          var watched = supportRecursive
+            ? [a, b, nested]
+            : [a, b, nested, ma, mb, mc]
+
+          assert.deepStrictEqual(
+            watched.sort(), paths.sort()
+          )
+
+          done()
+        })
+      })
+    })
+  })
+})

test/watch/builder.mjs

@@ -0,0 +1,234 @@
+import fs from 'fs/promises'
+import fsSync from 'fs'
+import path from 'path'
+import { fileURLToPath } from 'url'
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+
+let structure = `
+home/
+  a/
+    file1
+    file2
+  b/
+    file1
+    file2
+  c/
+  bb/
+    file1
+    file2
+  d/
+    file1
+    file2
+  e/
+    file1
+    file2
+    sub/
+  deep_node_modules/
+    ma/
+      file1
+      file2
+    mb/
+      file1
+      file2
+    mc/
+`
+
+let code = structure
+  .split('\n')
+  .filter(line => line)
+  .map(function(line) {
+    return {
+      indent: line.length - line.replace(/^\s+/,'').length,
+      type: /\/$/.test(line) ? 'dir': 'file',
+      text: line.replace(/^\s+|\s*\/\s*|\s+$/g, '')
+    }
+  })
+
+function join(arr) {
+  return arr.join('/')
+}
+
+function transform(arr) {
+  let result = []
+  let temp = []
+  let indent = 0
+  arr.forEach(function(line) {
+    if (!line.text) {
+      return
+    }
+    else if (!line.indent) {
+      temp.push(line.text)
+      result.push({type: line.type, text: join(temp) })
+    }
+    else if (indent < line.indent) {
+      temp.push(line.text)
+      result[result.length - 1].type = 'dir'
+      result.push({type: line.type, text: join(temp) })
+    }
+    else if (indent === line.indent) {
+      temp.pop()
+      temp.push(line.text)
+      result.push({type: line.type, text: join(temp) })
+    }
+    else if(indent > line.indent) {
+      temp.pop()
+      temp.pop()
+      temp.push(line.text)
+      result.push({type: line.type, text: join(temp) })
+    }
+
+    indent = line.indent
+  })
+  return result
+}
+
+function gracefully(promise) {
+  return promise.catch(function(err) {
+    console.log(err)
+  })
+}
+
+function emptyFile(target) {
+  let folder = target.slice(0, target.lastIndexOf('/'))
+
+  /*return fs.mkdir(folder, { recursive: true, force: true })
+    .then(() => fs.open(target, 'w').then(fd => fd.close()))*/
+
+  return fs.stat(folder)
+  .catch(() => fs.mkdir(folder, { recursive: true, force: true }))
+  .then(() => {
+    return fs.open(target, 'w').then(fd => fd.close())
+  })
+}
+
+export function Builder() {
+  this.root = path.join(__dirname, '__TREE__')
+  this.transformed = transform(code)
+}
+
+Builder.prototype.init = async function() {
+  await Promise.all(
+    this.transformed.filter(line => line.type === 'dir').map(line => {
+      let target = path.join(this.root, line.text)
+      return gracefully(fs.mkdir(target, { recursive: true }))
+    })
+  )
+  await Promise.all(
+    this.transformed.filter(line => line.type !== 'dir').map(line => {
+      let target = path.join(this.root, line.text)
+      return gracefully(emptyFile(target))
+    })
+  )
+}
+
+Builder.prototype.getPath = function(fpath, sub) {
+  return path.join(this.root, fpath, sub || '')
+}
+
+Builder.prototype.modify = function(fpath, delay) {
+  if (delay) throw new Error('remove delay')
+  let filePath = this.getPath(fpath)
+  return fs.appendFile(filePath, 'hello')
+}
+
+Builder.prototype.remove = function(fpath) {
+  let filePath = this.getPath(fpath)
+  return fs.rm(filePath, { recursive: true, force: true })
+}
+
+Builder.prototype.removeSync = function(fpath) {
+  let filePath = this.getPath(fpath)
+  return fsSync.rmSync(filePath, { recursive: true, force: true })
+}
+
+Builder.prototype.newFile = function(fpath, delay) {
+  if (delay) throw new Error('remove delay')
+  let filePath = this.getPath(fpath)
+  return emptyFile(filePath)
+}
+
+Builder.prototype.createDirectory = function(fpath) {
+  let filePath = this.getPath(fpath)
+  return fs.mkdir(filePath, { recursive: true })
+}
+
+Builder.prototype.randomName = function() {
+  return Math.random().toString(36).substring(2, 14)
+}
+
+Builder.prototype.newRandomFiles = function(fpath, count) {
+  return Promise.all(
+    new Array(count).fill(0).map(() => {
+      let name = this.randomName()
+      let filePath = this.getPath(fpath, name)
+
+      return emptyFile(filePath).then(() => name)
+    })
+  )
+}
+
+Builder.prototype.cleanup = function() {
+  return fs.rmdir(this.root)
+}
+
+Builder.prototype.getAllDirectories = function() {
+  function walk(dir) {
+    let ret = []
+    fsSync.readdirSync(dir).forEach(function(d) {
+      let fpath = path.join(dir, d)
+      if (fsSync.statSync(fpath).isDirectory()) {
+        ret.push(fpath)
+        ret = ret.concat(walk(fpath))
+      }
+    })
+    return ret
+  }
+  return walk(this.root)
+}
+
+export function Counter(res, countTotal, waitForSignal = false) {
+  this._res = res
+  this.counter = 0
+  this._countTotal = countTotal
+  this._startCount = !waitForSignal
+  this._gotSignal = false
+  this._signal = null
+}
+
+Counter.prototype.waitForCount = function(promise) {
+  if (!promise) {
+    promise = Promise.resolve()
+  }
+  return new Promise(res => {
+    promise.then(() => {
+      this._signal = res
+      this.hasSignal()
+    })
+  })
+}
+
+Counter.prototype.hasSignal = function() {
+  if (this._gotSignal && this._signal) {
+    this._gotSignal = false
+    let temp = this._signal
+    this._signal = null
+    temp()
+  }
+}
+
+Counter.prototype.startCounting = function() {
+  this._startCount = true
+}
+
+Counter.prototype.count = function() {
+  if (!this._startCount) return
+
+  this._gotSignal = true
+  this.counter++
+  if (this.counter === this._countTotal && this._res) {
+    this._res()
+  }
+
+  this.hasSignal()
+}