自定义promise

来源：互联网发布：中国m2历年数据增速编辑：程序博客网时间：2024/06/01 10:52

/* Promise */function Promise() {  this.queues = [];  this.fails = [];  this.progress = [];  this.nextVal = null;  this.nextErr = null;} Promise.prototype.then = function ( onFulfilled, onRejected, progress) {  this.done.call(this, onFulfilled);  if (Object.prototype.toString.call(onRejected) == "[object Function]") {    this.fail.call(this, onRejected);  }  if (Object.prototype.toString.call(progress) == "[object Function]") {    this.progress.call(this, progress);  }  return this;}; Promise.prototype.done = function (func) {  this.queues.push(function(data) {    this.nextVal = func.call(null, data);  });  return this; }; Promise.prototype.fail = function (func) {  this.fails.push( function(err) {    this.nextErr = func.call(null, err);  });}; /*  Deferred */function Deferred() {  this.status = 'pending';  this.promise = new Promise();} Deferred.prototype.resolve = function ( data) {  if (this.status == 'pending') {    this.promise.queues.forEach(function(func, i) {      func.call(this, this.nextVal || data);    }, this.promise);     this.status = 'fulfilled';  }}; Deferred.prototype.reject = function(err) {  if (this.status == 'pending') {    this.promise.fails.forEach(function(func, i) {      func.call(this, this.nextErr || err);    }, this.promise);    this.status = 'rejected';   }};  Deferred.when = function () {  var promises = Array.prototype.slice.call(arguments, 0), results = [], start = 0, total = promises.length, defer = new Deferred();   if (total === 0) return defer.resolve(results);  function notifier(index) {    return function(data) {      start += 1;      results[index] = data === undefined ? null : data;      if (start == total) {          defer.resolve(results);      }    }'  }   for (var i = 0; i < total; i++) {    // promise.done(function(data) { TODO }}    promises[i].done(notifier(i));  }   return defer.promise;}; Deferred.queues = function(funcs) {  var defer = new Deferred();  (function chain(data) {    if (funcs.length === 0)       defer.resolve(data);    else       funcs[0].call(null, data).done(function(d) {          funcs.splice(0, 1);          chain.call(null, d);       });  })();   reurn defer.promise;};

example

var defer = new Deferred();

defer.resolve('1111');

defer.reject(000);

defer.promise;

Deferred.when(defer.promise, defer.promise).done(function(d) { //DODO });

Deferred.queues([p1, p2, p3]).done(function(d) { //DODO });

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