modular
In NodeJS, there are two types of modules, system modules and custom modules.
System module
Nodejs: NodeJS: require() : nodeJS: nodeJS: nodeJS: nodeJS: nodeJS: nodeJS: nodeJS: nodeJS: nodeJS: nodeJS: nodeJS
- Path module: formalized path
const path=require('path');
var str='c:\\wamp\\www\\a.html'; var obj=path.parse(str); //base file name part //ext extension //dir path //name file name part console.log(obj);Copy the code
- Fs module: read and write operations to files
1.txt
This is the contents of 1.txtCopy the code
fs.js
const fs = require('fs')
var str = fs.readFile('./1.txt'.'utf-8'// This is the asynchronous operation console.log(STR) // this is the contents of 1.txtCopy the code
The second way to write it
fs.readFile('./1.txt', (err, data) => {
if (err) throw err;
console.log(data);
});
Copy the code
- Querystring: Parsed string
For example, the query string ‘foo=bar&abc=xyz&abc=123’ is parsed to:
{
foo: 'bar',
abc: ['xyz'.'123']}Copy the code
- Url: The module is used to process and parse urls
The usage is as follows
const url = require('url');
Copy the code
For the URL example, it is recommended that you actually operate on the document, personally recommended.
Custom modules
Custom modules are modules that we can write ourselves. Here I will briefly introduce the basic use of custom modules.
First, in NodeJS, a JS file can be called a module.
To use our module you must have two operations, export and import.
a.js
Var a = 1 module. Exports = a / / export a or module. The export = {a} / / here can export multiple properties or methodsCopy the code
b.js
var moduleA = require('./a.js'Console. log(modulea.a) // Output 1Copy the code
Publish our modules through NPM
Here I simply say the release method, specific we can go to Baidu, that is more detailed than me
1. Register an NPM account
2. Log in to the NPM using the CMD command line interface
3. Publish directly to your NPM repository via NPM command (very crude…)
This is the basics of nodeJS modularity. If there is something wrong with it, please feel free to make fun of it.