es6中promise ALL Race Resolve Reject finish的实现

function mypromise(func){
        this.statue = "pending";
        this.data = null;
        this.resolveCallback = [];
        this.rejectCallback = [];
        this._final = null;
        var self = this;
        var resolve = function(data){
          if (data instanceof mypromise) {
            data.then(resolve,reject)
            return;
          }
          setTimeout(function(){
            if(self.statue != "pending") return;
            self.data = data;
            self.statue = "resolve";
            for(var i = 0; i < self.resolveCallback.length; i++){
              var item = self.resolveCallback[i];
              item.bind(self)(data)
            }
          },0)
        }
        var reject = function(data){
          setTimeout(function(){
            if(self.statue != "pending") return;
            self.data = data;
            self.statue = "reject";
            for(var i = 0; i < self.rejectCallback.length; i++){
              var item = self.rejectCallback[i];
              item.bind(self)(data)
            }
          },0)
        }
        try {
          if (typeof func == ‘function‘){
            func.bind(this)(resolve,reject);
          }else{
            if(func == ‘reject‘){
              this.statue = "reject";
              reject();
            }else{
              this.statue = "resolve";
              resolve();
            }
          }
        } catch (e) {
          reject(e)
        }
      }
      mypromise.prototype.then = function(onresolve,onreject){
        var self = this;
        onresolve = typeof onresolve === ‘function‘ ? onresolve : function(data){return data;}
        onreject = typeof onreject === ‘function‘ ? onreject : function(data){return data;}
        if(self.statue == "pending"){
          return new mypromise(function(resolve,reject){
            var _this = this;
            self.resolveCallback.push(function(data){
              var x = onresolve(data);
              if(x instanceof mypromise){
                x.then(resolve,reject)
              }else{
                resolve(x)
              }
              typeof _this._final == ‘function‘ ? _this._final() : null;
            })

            self.rejectCallback.push(function(data){
              var x = onreject(data);
              if(x instanceof mypromise){
                x.then(resolve,reject)
              }else{
                reject(x)
              }
              typeof _this._final == ‘function‘ ? _this._final() : null;
            })

          });
        }
        if(self.statue == "resolve"){
          return new mypromise(function(resolve,reject){
            var x = onresolve(self.data);
            if(x instanceof mypromise){
              x.then(resolve,reject)
            }else {
              resolve(x);
            }
            typeof this._final == ‘function‘ ? this._final() : null;
          });
        }
        if(self.statue == "reject"){
          return new mypromise(function(resolve,reject){
            var x = onreject(self.data);
            if(x instanceof mypromise){
              x.then(resolve,reject)
            }else {
              reject(x);
            }
            typeof this._final == ‘function‘ ? this._final() : null;
          });
        }
      }
      mypromise.prototype.catch = function(reject){
        return this.then(null,reject);
      }

      mypromise.All = function(){
        var allArguments = arguments;
        var len = allArguments.length,
            item = null,
            successResult = [],
            failResult = []
            resultData = [];
        return new mypromise(function(resolve,reject){
          function resolver(index){
            return function(data){
              successResult.push(1);
              resolveAll(index,data);
            }
          }
          function rejecter(index){
            return function(data){
              failResult.push(1);
              resolveAll(index,data);
            }
          }
          function resolveAll(index,data){
            resultData.push({index:index,data:data})
            if(successResult.length + failResult.length == len){
              if( successResult.length == len){
                resolve(resultData)
              }else{
                reject(data)
              }
            }
          }
          for(var i = 0; i < len; i++){
            item = allArguments[i];
            if(!(item instanceof mypromise)){
              throw new TypeError("you must pass promise to mypromise.all")
            }
            item.then(resolver(i),rejecter(i))
          }
        })
      }
      mypromise.Race = function(){
        var allArguments = arguments;
        var len = allArguments.length,
            item = null,
            successResult = [],
            failResult = [];
        return new mypromise(function(resolve,reject){
          function resolver(data){
            successResult.push(1);
            resolveAll(data);
          }
          function rejecter(data){
              failResult.push(1);
              reject(data);
          }
          function resolveAll(data){
            resolve(data)
          }
          for(var i = 0; i < len; i++){
            item = allArguments[i];
            if(!(item instanceof mypromise)){
              throw new TypeError("you must pass promise to mypromise.all")
            }
            item.then(resolver,rejecter)
          }
        })
      }
      mypromise.Resolve = function(func){
        if(func instanceof mypromise){
          return func;
        }else{
          return new mypromise(‘resolve‘);
        }
      }
      mypromise.Reject = function(func){
        return new mypromise(‘reject‘);
      }
      mypromise.prototype.Final = function(onresolve){
        this._final = onresolve;
      }

原文地址：https://www.cnblogs.com/mrzhu/p/8457058.html