var Promise = require('bluebird'); Promise.join( function A() { console.log("A"); },function B() { console.log("B"); } ).done( function done() { console.log("done");} );
控制台将记录
B done
不过我会期待
A B done
要么
B A done
解决方法
Promise.join(Promise.delay(100),request("http://...com"),function(_,res){ // 100 ms have passed and the request has returned. });
你给它两个功能,所以它执行以下操作:
>对函数A(){…}做出承诺 – 基本上是对它做出承诺
>当完成(立即)执行最后一个参数时,函数B(){…}记录它.
查看文档:
Promise.join(Promise|Thenable|value promises...,Function handler) -> Promise
For coordinating multiple concurrent discrete promises. While .all() is good for handling a dynamically sized list of uniform promises,Promise.join is much easier (and more performant) to use when you have a fixed amount of discrete promises that you want to coordinate concurrently,for example:
var Promise = require("bluebird");
var join = Promise.join;
join(getPictures(),getComments(),getTweets(),
function(pictures,comments,tweets) {
console.log("in total: " + pictures.length + comments.length + tweets.length);
});
更新:
JSRishe想出了另一个聪明的方式来解决这种模式in this answer,它看起来像:
Promise.delay(100).return(request("http://...com").then(function(res){ // 100 ms have passed and the request has returned });
原文地址:https://www.jb51.cc/js/155603.html
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