How do I reduce multiple Promise.all?

I am trying to use a Promise.all inside of a reduce and cannot get my function to work, unless there is only one user in my array. The starting object of the reduce is a Promise . The first time through the reduce , the Promise has .all available on it. The second time through, the .all is not available. return UserQueries.addUsersOnCasefileCreate(input).then(users => { return users.redu

我如何减少多个Promise.all?

我试图用一个Promise.all内部的reduce ,不能让我的function工作,除非只有一个在我的阵列的用户。 reduce的起始目标是一个Promise 。 第一次通过reduce的Promise有.all的可供使用。 第二次通过, .all不可用。 return UserQueries.addUsersOnCasefileCreate(input).then(users => { return users.reduce((promise, user) => { return promise.all([ AddressQueries.addAddress(user.address, user.userId,

How do I convert an existing callback API to promises?

I want to work with promises but I have a callback API in a format like: 1. DOM load or other one time event: window.onload; // set to callback ... window.onload = function(){ }; 2. Plain callback: function request(onChangeHandler){ ... } request(function(){ // change happened ... }); 3. Node style callback ("nodeback"): function getStuff(dat,callback){ ... } get

如何将现有的回调API转换为承诺?

我想使用承诺,但我有一个格式的回调API: 1. DOM负载或其他一次性事件: window.onload; // set to callback ... window.onload = function(){ }; 2.普通回调: function request(onChangeHandler){ ... } request(function(){ // change happened ... }); 3.节点样式回调(“nodeback”): function getStuff(dat,callback){ ... } getStuff("dataParam",function(err,data){ ... }) 4.具有节点样

Aren't promises just callbacks?

I've been developing JavaScript for a few years and I don't understand the fuss about promises at all. It seems like all I do is change: api(function(result){ api2(function(result2){ api3(function(result3){ // do work }); }); }); Which I could use a library like async for anyway, with something like: api().then(function(result){ api2().then(f

不承诺只是回调?

我几年来一直在开发JavaScript,而且我根本不了解承诺的大惊小怪。 看起来我所做的只是改变: api(function(result){ api2(function(result2){ api3(function(result3){ // do work }); }); }); 无论如何,我可以使用类似async的库,例如: api().then(function(result){ api2().then(function(result2){ api3().then(function(result3){ // do work

How synchronous AJAX call could cause memory leak?

I understand this general advice given against the use of synchronous ajax calls, because the synchronous calls block the UI rendering. The other reason generally given is memory leak isssues with synchronous AJAX. From the MDN docs - Note: You shouldn't use synchronous XMLHttpRequests because, due to the inherently asynchronous nature of networking, there are various ways memory and ev

如何同步AJAX调用可能导致内存泄漏?

我明白这个一般建议是针对使用同步ajax调用给出的,因为同步调用会阻止UI呈现。 通常给出的另一个原因是与同步 AJAX的内存泄漏问题。 从MDN文档 - 注意:不应该使用同步XMLHttpRequests,因为由于网络固有的异步性质,在使用同步请求时存在内存和事件泄漏的各种方式。 唯一的例外是同步请求在Worker中很好地工作。 同步调用如何导致内存泄漏? 我正在寻找一个实际的例子。 任何关于这个主题的文献都会很棒。 如果

How do I get started with Node.js

Are there any good resources to get started with Node.JS? Any good tutorials, blogs or books? Of course, I have visited its official website http://nodejs.org/, but I didn't think the documentation they have is a good starting point. Tutorials NodeSchool.io interactive lessons The Art of Node (an introduction to Node.js) Hello World Hello World Web Server (paid) Node.js guide

我如何开始使用Node.js

有没有好的资源可以开始使用Node.JS? 任何好的教程,博客或书籍? 当然,我访问过它的官方网站http://nodejs.org/,但我不认为他们拥有的文档是一个很好的起点。 教程 NodeSchool.io互动课程 节点的艺术(对Node.js的介绍) 你好,世界 Hello World Web Server(付费) Node.js指南 使用Node.js,express和MongoDB构建博客 初学者的Node.js 完全自信地学习Node.js 节点JS处理模型 - 具有事件循环体系结

How do I debug Node.js applications?

How do I debug a Node.js server application? Right now I'm mostly using alert debugging with print statements like this: sys.puts(sys.inspect(someVariable)); There must be a better way to debug. I know that Google Chrome has a command-line debugger. Is this debugger available for Node.js as well? node-inspector could save the day! Use it from any browser supporting WebSocket. Breakp

我如何调试Node.js应用程序?

我如何调试Node.js服务器应用程序? 现在,我主要使用像这样的打印语句使用警报调试: sys.puts(sys.inspect(someVariable)); 必须有更好的调试方法。 我知道Google Chrome有一个命令行调试器。 这个调试器是否也可用于Node.js? 节点检查员可以节省一天的时间! 从任何支持WebSocket的浏览器使用它。 断点,分析器,生活编码等等。这真的很棒。 安装它: npm install -g node-inspector 然后运行: node-debug ap

How can I parse records on demand with Node.js?

Is there a Node module that can parse a specific number of records from a CSV file? The use case is to parse a large log file and deliver records to a paging client as requested. node-csv can't yet do this, and the closest I've found is to read lines one by one, which requires reinventing the CSV parsing wheel, and will break on multi-line records. But let's lower the bar: how ca

如何使用Node.js按需分析记录?

有没有一个Node模块可以解析CSV文件中的特定数量的记录? 用例是解析一个大的日志文件并根据请求将记录传递给分页客户端。 node-csv还不能做到这一点,而我发现的最接近的是逐行读取行,这需要重新创建CSV解析轮,并且会在多行记录中破解。 但是让我们放下吧:我如何使用Node.js逐一解析单行CSV记录? 在大多数其他语言中很琐碎的任务。 据我所知,你只是想将逗号分隔的一行值解析成一个数组? 如果是这样,请尝试这一

Read a file one line at a time in node.js?

I am trying to read a large file one line at a time. I found a question on Quora that dealt with the subject but I'm missing some connections to make the whole thing fit together. var Lazy=require("lazy"); new Lazy(process.stdin) .lines .forEach( function(line) { console.log(line.toString()); } ); process.stdin.resume(); The bit that I'

在node.js中一次读取一行文件?

我正在尝试一次读取大文件一行。 我在Quora上发现了一个关于这个问题的问题,但我错过了一些联系以使整个事情合在一起。 var Lazy=require("lazy"); new Lazy(process.stdin) .lines .forEach( function(line) { console.log(line.toString()); } ); process.stdin.resume(); 我想知道的一点是,我可能会如此示例一次从文件而不是STDIN读取一行。 我试过了: fs.open('

Javascript: closures? eventlistener won't add

I seem to have a problem, and I suspect it's a problem with closures. I got 3 buttons, and when I run this code only the last button gets an eventlistener. This is why I suspect a closures problem. I tried all sorts of things as create other functions but the didn't help me. In the function addListeners i have 3 console.logs with information and they display the RIGHT information. So

Javascript:关闭? eventlistener不会添加

我似乎有一个问题,我怀疑这是关闭的问题。 我得到了3个按钮,当我运行这个代码时,只有最后一个按钮获得了一个eventlistener。 这就是为什么我怀疑封闭问题。 我尝试了各种各样的创造其他功能的东西,但没有帮助我。 在函数addListeners中,我有3个console.logs和信息,它们显示RIGHT信息。 所以在addeventlisteners中,我有正确的DIV,有正确的信息,但没有添加监听器。 任何人都可以帮我在这里吗? 我不知道我在做什么

Loop inside React JSX

I'm trying to do something like the following in React JSX (where ObjectRow is a separate component): <tbody> for (var i=0; i < numrows; i++) { <ObjectRow/> } </tbody> I realize and understand why this isn't valid JSX, since JSX maps to function calls. However, coming from template land and being new to JSX, I am unsure how I would achieve the abov

在React JSX中循环

我正在尝试在React JSX(其中ObjectRow是一个单独的组件)中执行以下操作: <tbody> for (var i=0; i < numrows; i++) { <ObjectRow/> } </tbody> 我意识到并理解为什么这不是有效的JSX,因为JSX映射到函数调用。 但是,来自模板领域并且是JSX的新手,我不确定如何实现上述目标(多次添加组件)。 把它想象成你只是在调用JavaScript函数。 你不能在函数调用中放置一个for循环: ret