本文讲详细讲解 nodejs 中两个比较难以理解的部分异步I/O和事件循环,对 nodejs 核心知识点,做梳理和补充。 送人玫瑰,手有余香,希望阅读后感觉不错的同学,可以给点个赞,鼓励我继续创作前端硬文。 老规矩我们带上疑问开始今天的分析🤔🤔🤔: 1 说说 nodejs 的异步I/O ? 2 说说 nodejs 的事件循环机制 ...
My problem comes when a plugin function makes an async request (to get data from mongo in this case) this causes the plugin code to finish and return control back to the original emitter which will then complete execution, before the async request in the plugin code finishes. E.g: Main A...
NodeJS parallel不等待并行函数如果你使用3.x版本的async，我们有一个很大的变化-支持async/await，版本...
1.切换到数据库体系结构，这样每次进行更改时，都将该更改写入数据库（使用持久性存储的数据库）。然后...
for (const el of cNodes) { imgsData.push(el.firstChild) } const preload = new Preload(imgsData) await preload.doms() // 实例化上面的Preload函数,开始轮询资源 console.log('--> 加载完成,可以开始截图') try { window.loadFinishToInject('done') // 触发`Puppeteer`的注入方法 ...
function a(){ b() } function b(){ c() } function c(){ console.log(new Error().stack) } a() 打印结果如下 Error at c (/Users/yj/projects/node-debug/examples/async_hooks/app_sync.js:8:15) at b (/Users/yj/projects/node-debug/examples/async_hooks/app_sync.js:5:3) at a ...
page.on('load',async() => {awaitautoScroll()// 自动截图时先模拟滚动awaitsleep(wait)// 前面实现的等待方法// 开始截图awaitpage.screenshot({ path,fullPage:true})// 关闭浏览器awaitbrowser.close() }) 这样当页面加载完成后,就会触发自动滚动,每100毫秒向下滚100像素,直到触底为止,跳出Promise,配合前...
在一个流被提前销毁(像中断HTTP请求)并且不会发射’end’或者’finish’的情况下非常的有用。 finished API同样可以promise化; const finished = util.promisify(stream.finished); const rs = fs.createReadStream('archive.tar'); async function run() { await finished(rs); console.log('Stream is done ...
[function]- Callback to be invoked when avery baderror occurs. If this is invoked it means that v8 has lost all control over the isolate, and all resources in use are totally unrecoverable. If you receive this error you should log the error, stop serving requests, finish outstanding work,...
log("Server is running http://localhost:3000/"); }); async function getHeaders() { const response = await axios({ method: "get", url: "http://headers.jsontest.com/", }); return response.data; } Copy If we run the application and make a couple of requests, we will see that ...