Node 项目中常见的问题及解决方法

"scripts": {
   "start": "export NODE_ENV=development && nodemon -w src --exec \"babel-node src\"",
   "build": "babel src --out-dir dist",
   "run-build": "node dist",
   "test": "echo \"Error: no test specified\" && exit 1"
 }

"scripts": {
   "start": "set NODE_ENV=development && nodemon -w src --exec \"babel-node src\""
 }

npm install -g node-gyp

router.post('api/validVip',(ctx) => {
    ctx.cookies.set(
        'vid', 'aiguangyuan', { maxAge: 24 * 3600 * 1000 }
    );
});

ctx.cookies.set('vid', '', { maxAge: 0 });

import koa from 'koa';
import http from 'http';

const app = new koa();
const server = http.createServer(app.callback());
const io = require('socket.io')(server);

//  正常的业务处理
io.on('connection', (socket) => {
    console.log('a user connected');
    socket.on('doc load', (msg) => {
        console.log('doc load', msg)
        io.emit('getData', users)
    })
});

server.listen(3000, () => {
    // ...
});

// 更新最新的包
npm i xxx@latest

// 使用包管理工具n
npm i -g n

let schedule = require('node-schedule');

let testJob = schedule.scheduleJob('42 * * * *', function(){
    console.log('将在未来的每个时刻的42分时执行此代码, 比如22:42, 23:42');
});

# .babelrc
{
  "presets": [
    [
      "@babel/preset-env",
      {
        "targets": {
          "node": "current"
        }
      }
    ]
  ],
  "plugins": [
    ["@babel/plugin-proposal-decorators", { "legacy": true }],
    ["@babel/plugin-proposal-class-properties", { "loose" : true }]
  ]
}

yarn add 
@babel/cli 
@babel/core 
@babel/node 
@babel/plugin-proposal-class-properties 
@babel/plugin-proposal-decorators 
@babel/preset-env

const fastJson = require('fast-json-stringify')
const stringify = fastJson({
  title: 'H5 Dooring Schema',
  type: 'object',
  properties: {
    firstName: {
      type: 'string'
    },
    lastName: {
      type: 'string'
    },
    age: {
      description: 'Age in years',
      type: 'integer'
    },
    reg: {
      type: 'string'
    }
  }
})

const json = require('jsonfile')；
const fileName = 'h5-dooring.json'；
const jsonData = jsonFile.readFileSync(fileName)；

const fs = require("fs");
const path = require("path");
const readline = require("readline");

const readlineTask = readline.createInterface({
    input: fs.createReadStream(path.join(__dirname, './h5-dooring')),
});
 
readlineTask.on('line', function(chunk) {
  // 读取每一行数据
});
 
readlineTask.on('close', function() {
  //文件读取结束的逻辑
}

import koa from 'koa';
import compress from 'koa-compress';

const app = new koa();

// 开启gzip
const options = { threshold: 2048 };
app.use(compress(options));

import os from 'os'
const _$ = (os.platform().toLowerCase() === 'win32') ? '\\' : '/';

// child.js
function computedTotal(arr, cb) {
    // 耗时计算任务
    
}

// 与主进程通信
// 监听主进程信号
process.on('message', (msg) => {
  computedTotal(bigDataArr, (flag) => {
    // 向主进程发送完成信号
    process.send(flag);
  })
});

// main.js
const { fork } = require('child_process');

app.use(async (ctx, next) => {
  if(ctx.url === '/fetch') {
    const data = ctx.request.body;
    // 通知子进程开始执行任务,并传入数据
    const res = await createPromisefork('./child.js', data)
  }
  
  // 创建异步线程
  function createPromisefork(childUrl, data) {
    // 加载子进程
    const res = fork(childUrl)
    // 通知子进程开始work
    data && res.send(data)
    return new Promise(reslove => {
        res.on('message', f => {
            reslove(f)
        })
    })  
  }
  
  await next()
})

const images = require("images");

images("input.jpg")                     // 加载图像文件                            
  .size(400)                            // 等比缩放图像到400像素宽
  .draw(images("logo.png"), 10, 10)     // 在(10,10)处绘制Logo
  .save("output.jpg", {                 // 保存图片到文件,图片质量为50
      quality : 50                    
  });