Chrome debugging

——从入门到玄学大师

node index.js --inspect

  1. node --inspect-brk index.js
  2. chrome://inspect
  3. find remote target
  4. click inspect

P.S. node -e "process._debugProcess(PID)" for node process

P.S. 使用 command + p 切换文件

vscode debugging

  1. add launch.json
  2. click vscode Launch
  1. hot breakpoint
  2. multiple​ mode
  3. easy to use
  4. more language support

e.g. python/c#/cpp/ts/coffee ...

1. launch program directly

2. Attach by Process ID

3. Remote debugging

chrome

1.performance

2.network

2.network

const http = require('http')
const port = 3000

const server = http.createServer(function(request, response) {
  response.setHeader('Server-Timing', `cache=2; "Cache Read", db=1; "Database Read", process=1.5; "Process Request"`)
  response.end('Hello Core!')
})

server.listen(port, function() {
  console.log(`Listening on http://localhost:${port}`)
})

3.1 Memory Summary

  • Distance:ref 到 root 的距离
  • Shallow Size: 直接占用内存
  • Retained Size: 占用总内存
  • Object count: 对象的实例数

3.2 Profile allocation

3.3 Live chart

3.4 Other Tools

internal tools

chrome://about

 

dns

net-internal

tracing

上上下下左右左右ABAB

在这个界面按6下 shift 可以出现隐藏功能

CPU Profile

 

chrome 61 改了输出格式,所以市面上暂时没什么工具可以解析

否则可以用oneprofile这类文件可视化函数 call stack 同时显示 v8 deopz 原因,不过下一个版本 node 都换v8 引擎了,又有大批deopz的原因可以不用记了

setTimeout debugging

// ui debug only
// chrome only


setTimeout(function() {
  debugger
}, 10000)

console

  1. console.dir
  2. console.trace
  3. console.profile
  4. console.time & console.timeEnd()
  5. store as temp vars

console.dir

console.trace

console.profile

Chrome debugging

By 知白 Saviio

Chrome debugging

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