360 Front-end Star Project-Basic Introduction to Node.js (Li Zheming)

1. What is Node.js

It is a platform built based on chrome js runtime and based on V8 engine. Simply put, Node.js is JavaScript running on the server.

The difference with JS:

• Based on asynchronous I / O related interface
• Module dependencies based on node_modules and require
• Provide C ++ plugin API to interact with the underlying system

What can Node.js do?

• Web server: Web Server, crawler
• CLI command line script: webpack
• GUI client software: VSCode, NetEase Cloud Music
• loT, image processing, real-time communication, cryptocurrency ...

2. Node.js basics

2.1 Module

• Built-in modules: compiled into Node, such as http fs net process path, etc. fs = require('fs')
• File module: modules other than native modules, one-to-one correspondence with files (folders) require('./circle.js')

2.2 Module loading

// 加载绝对路径文件
require('/foo/bar/a.js');
// 加载相对路径文件
require('../a.js');
// 加载无后缀的文件
require('../a');
// 加载外部模块
require('pkg-name'); //从当前或上级或上上级查找直到查到底层根目录

2.3 Module type

• .js
• .json forms js object
• .node binary
• .mjs
• …

2.4 Module path search

• Absolute path
• relative path
  • And the current path is treated as an absolute path
• Module / folder
  • Native module, read cache directly
  • [$NODE_PATH, ~/.node_modules,
    ./node_modules, …/node_modules, …]
  • Parse package.json to find the main attribute, if not, use index.js
  • If not found, an error is reported

2.5 js module analysis

• Get the file content synchronously through fs.readFileSync

• Pack content (closure)

  (function (exports, require, module, __filename, __dirname) {
      var circle = require('./circle.js');
      console.log('The area is ' + circle.area(4));
  });
  

• Execute through vm.runInThisContext

• Get the value of the module object as the return value of the module

2.6 Module cache

• After the module is loaded, the return value is cached
• Read the cached result directly at the next load to avoid file I / O and parsing time
• The exported object is cached on the Module._cache object

3. NPM

3.1 Package management

• A package.json file should exist in the top-level directory of the package
• Binary files should be included in the bin directory
• JavaScript code should be included in the lib directory
• The document should be in the doc directory
• Unit tests should be in the test directory

3.2 Package dependencies

"dependencies": {
    "accepts": "^1.2.2",
    "content-disposition": "~0.5.0",
    "cookies": "~0.7.0",
    "debug": "*",
    "delegates": "^1.0.0",
    "escape-html": "~1.0.1",
    "fresh": "^0.5.2",
    "only": "0.0.2",
    "parseurl": "^1.3.0",
    "statuses": "^1.2.0",
    "type-is": "^1.5.5",
    "vary": "^1.0.0"
  },

3.3 NPM issues

• Speed ​​problem
• safe question
  • View source code to see Star
  • https://snyk.io/ External inspection service
  • asl audit

4. Web development based on Node.js

• Koa: The role of middleware is not regulated and is not conducive to team development. There are many middleware, uneven quality and difficult selection.

• ThinkJS: specifies the project structure
  ├─src
  │ ├─bootstrap
  │ ├─config
  │ │ ├─config.js
  │ │ └─adapter.js
  │ ├─controller //
  routing│
  │ ├─index.js
  │ ├─logic │ │ ├─index.js
  │ └─model // database
  ├─view // template
  file│
  ├─index_index.html └─www // static resource│
  └─static
  │ ├─css
  │ ├─img
  │ └─js
  ├ ─development.js
  ├─production.js
  ├─package.json

TODO List project combat

function list

• TODO List page
• API (RESTful interface specification)
  • Get TOO list
  • Increase TODO
  • Remove TODO
    -Update TODO status

RESTful interface specification

• Each API corresponds to a resource or collection of resources
• Use HTTP Method to represent actions on resources
• Use HTTP Status Code to represent resource operation results

Data validation

• Logic mechanism revolving door is provided to support data verification
• File and Action correspond to Controller one by one

Model benefits

• Simplify code and increase efficiency
• Can operate the database without too much understanding of SQL statements
• Avoid the security risks of handwritten SQL statements

5. Debugging Node.js

debugging

Reference: Use ndb debug your project Node.js

• Log debugging
• Breakpoint debugging
  • node --inspect
  • vscode
  • ndb

Node development role change

• front end
  • Dealing with browsers, compatibility issues
  • Componentization
  • Loading speed, JS execution performance, rendering performance
  • Error monitoring
  • XSS, CSRF and other security vulnerabilities
• Server
  • Database, Redis and other peripheral services
  • Performance, memory leaks, CPU, machine management
  • Service monitoring, error monitoring, flow monitoring, alarm
  • SQL injection, directory traversal and other security vulnerabilities