Overview of Node development

1.1 Why learn the basics of server-side development

Be able to work more closely with back-end programmers

Website business logic in front, learning front-end technology needs back-end technology support (Ajax)

Broaden your knowledge horizon and look at the whole project from a higher perspective

1.2 Things to do in server-side development

Implement the business logic of the website

Add, delete, change and check data

1.3 Why Choose Node

①Node is a platform based on the Chrome JavaScript runtime, for easy to build, fast response, easy to web applications extension.

② As web front-end developers need to understand a background language

③ NodeJS is easier to use for front-end developers

1.4 What is a Node

Node is a JavaScript environment based on the Chrome V8 engine.

Runtime environment

The browser (software) can run JavaScript code, and the browser is the environment in which JavaScript code runs >Node (software) can run JavaScript code

2.Node running environment construction

2.1 Installing the Node.js Operating environment

Liverpoolfc.tv: nodejs.org/en/

LTS = Long Term Support Stable version Current Has the latest feature experimental version

2.2 Solution to Node Environment Installation Failure

1. Error code 2502, 2503

Cause: The system account has insufficient permissions.

Solution: Run the powershell command line tool as an administrator and run the msiexec /package node command to locate the installation package

2. An error occurs when the command is executed

Cause: The Node installation directory fails to write environment variables

Workaround: Add the Node installation directory to the environment variable

2.3 PATH Environment Variable

Directories in the storage system. When you run a command on the cli, the system automatically searches for the command location in these directories.

Quick start with Node.js

3.1 Composition of Node.js

JavaScript consists of three parts: ECMAScript, DOM, and BOM.

Node.js is made up of additional apis provided by ECMAScript and the Node environment, including files, networks, paths, and more powerful apis.

3.2 Basic Syntax of Node.js

All ECMAScript syntax is available in the Node environment.

To execute the code in the Node environment, use the Node command to execute the.js file

3.3 Node.js Global object global

In the browser the global object is window, in Node the global object is global.

Node has the following methods under global objects, which can be used anywhere. Global can be omitted.

Console.log () is printed in the console

var first = 'hello nodejs'; console.log(first); Function fn (){console.log('fn function was called '); ]  } fn (); for (var i = 0; i <5; i ++) { console.log(i); } if (true){ console.log('123'); } console.log(' File has been modified ')Copy the code

SetTimeout () Sets the timeout timer

setTimeout(function (){ console.log('123'); }, 2000).Copy the code

ClearTimeout () Clears the timeout timer

SetInterval () sets the interval timer

ClearInterval () Clears the intermittent timer