Try to use Node.js to stumble and stumble in your work. Briefly comb Noejs (7 days) from now on, leaving out the following points of knowledge in the example section:

require and export

Export methods or variables from a file using the export or module.exports method in the target component

The difference is that export is not available when exporting a single variable or method

A simpler way to distinguish: forget how export is exported

require is used to accept functions or methods that components export through module.export

// a.js export
function add (e) { ...... }
module.exports.add(e)
// b.js import
var a = require('a')
a.add(1) // Using methods in a.js

Exporting through the export or module.export method is a collection of objects

http core module

var http = require('http') // Introducing http core modules
var server = http.createServer() // Create a server service
server.on('request', (request, response) => {
    // Request to get request data
    // Response returns response data
})
server.listen(3000, () => {...}) // Listen on port number 3000

url core module

• url.parse(urlStr[, parseQueryString[, slashesDenoteHost]])

  urlStr url string

  When parseQueryString is true, the query string will be parsed using the query module, defaulting to false

• url.pathname

  Gets and sets the path portion of the URL

• url.query

  Get the URL parameter section (? After)

Assume the page request address is/url?Name=sfatpaper&data=20191129

var http = require('http')// Introducing http core modules
var url = require('url') // Introducing url core modules
http.createServer((req, res) => {
    var parseObj = url.parse(req.url, true) // Use the url.parse method to get the object requesting the URL
    var pathName = parseObj.pathname // /url
    var pathQuery = parseObj.query // {name: sfatpaper, data: 20191129}
    // var parseObj = url.parse(req.url)
    // var pathQuery = parseObj.query // name=sfatpaper&data=20191129
})

Nodemon

Nodemon is a usage tool that will meet to monitor any changes in the source file and automatically restart the server.Nodemon doesn't make any additional changes to your code, it's just a replacement for the node command

install

npm install --global nodemon

Example

// Change node demo.js of previously run code to
nodemon demo.js

art-template template engine

art-template is a simple, ultra fast template engine

install

npm install art-template --save

Example

var template = require('art-template') // Introducing art-template components
template.render(source, data, options)
// The template string source needs to export
// Data needs to be replaced with a data object in the template string

Express Framework

Be based on Node.js Platform, Fast, Open, Minimalist Web Development Framework

install

npm install express --save

Example

var express = require('express')  // Introducing express components
var app = express()
app.get('/', (req, res) => res.send('Hello World!')) // Processing get requests
app.listen(3000, () => {...}) // Listen on port number 3000

Express-art-template

Express-art-template is a third-party component specifically designed to support the template template engine in Express

install

npm i art-template

To configure

app.engine('html', require('express-art-template'))

Example

app.engine('html', require('express-art-template')) // Configure art-template
app.render(source, data, options)
// The template string source needs to export
// Data needs to be replaced with a data object in the template string

body-parser

express does not provide a way to get the corresponding requester in the post request mode, so the body-parser component is needed to process the response request

install

npm install --save body-parser

To configure

app.use(bodyParser.urlencoded({
	extended: false
}))
app.use(bodyParser.json())

Example

var bodyParser = require('body-parser') // Introducing components
app.use(bodyParser.urlencoded({ // Configuring components
	extended: false
}))
app.use(bodyParser.json())
app.post('/post', (req, res) => {
    console.log(req.body) // req.body gets post body
})

MongoDB database

MongoDB is a non-relational database

install

Installation File Download Address: [ https://www.mongodb.com/download-center/community]

Special attention is required during installation to remove the default check before Install MongoDB Compass

You can use the mongod --version command to view the MongoDB version and install it if the version number output is normal

Use

• Start database mongodb By default, the database directory launched by the command executes in the drive letter root directory/data/db file where the command executes
• Replace database directory mongod --dbpath ='Database self-proposed path'
• Connect MongoDB service mongodb
• Show all existing databases show dbs
• Switch to target database use'Database name'
• View current operational database db
• Displays all collections of the current database show'Database name'
• Displays all data in the database collection db.'Database name'.find()
• Add data db.'Database name'.insertOne({data object}) to the database collection
• Disconnect the MongoDB service exit

Mongoose

Mongoose is an object model tool that facilitates the operation of mongodb in the node.js asynchronous environment

install

npm install mongoose

Example

var mongoose = require('mongoose'); // Introducing mongoose
mongoose.connect('mongodb://localhost/test'; //connect to mongodb database via mongoose

The default port to connect to the database is 27017

var db = mongoose.connection; // Database Connection Status
db.on('error', console.error.bind(console, 'connection error:')); // Database Connection Failure
db.once('open', function() {
  // we're connected! (Database connection successful)
});

.connection returns a pending connection that we can monitor for success

var Kitten = mongoose.model('Kitten', mongoose.Schema({
        // name: String,
        // You can also write as follows
        name: {
            type: String, // data type
            required: Boolean, // Is it necessary
            defaule: 'Zhang San', // Default value
            enum: ['Zhang San', 'Li Si', 'King Five', 'Zhao Six'] // Enumeration, default value is only enumeration value
        }
    });
);

Before you can manipulate the database, you need to pre-design the data formats in the collection, such as the code above

A collection named Kitten was created with a data name and a string type in the data structure inside the collection

• Add data

  Model.save([fn])

  var user = new User({ // Add a new data
  	username: 'kongzhi0707',
    	password: '123456'
  });
  user.save(function(err, res) { // Save data in database
    	if (err) {
      	return console.log(err);
    	}  
    	console.log(res);
  });
  

• Delete data

  Model.remove(conditions, [callback]) Deletes all eligible documents from the collection

  Model.findByIdAndRemove(id, [options], [callback]) Finds documents matching the ID and deletes them

  Model.findOneAndRemove(conditions, [options], [callback]) by record

  var wherestr = {'username': 'kongzhi0707'}; // Conditions for deleting data
  User.remove(wherestr, function(err, res) {
    		if (err) {
        	return console.log(err);
    	}  
    	console.log(res);
  });
  

• Update Data

  Model.update(conditions, doc, [options], [callback]) Updates a document in the database based on conditions

  Model.findByIdAndUpdate(id, [update], [options], [callback]) Updates a document in the database through its ID field

  Model.findOneAndUpdate([conditions], [update], [options], [callback]) based on record

  var wherestr = {'username': 'kongzhi0707'}; // Conditional queries to update data
  var updatestr = {'password': 'abcdef'}; // Perform Update Data
  User.update(wherestr, updatestr, function(err, res) {
  	if (err) {
        	return console.log(err);
    	}  
  	console.log(res);
  });
  

• Query Data

  Model.find(conditions, [fields], [options], [callback]) Finds files based on conditions

  Model.findById(id, [projection], [options], [callback]) finds a single document through its ID field

  Model.findOne([conditions], [projection], [options], [callback]) based on records

  var wherestr = {'userName': 'Lon 0707'}; // Conditions for deleting data
  User.find(wherestr, function(err, res) {
  	if (err) {
      	return console.log(err);
  	}  
  	console.log(res);
  });
  

The article has synchronized with my personal blog: ' Node Learning Notes 7-day Course Knowledge Arrangement>

Related articles:

• Node Learning Notes fs.readFile, fs.writeFile, fs.readdir
• Node Learning Notes http.createServer, art-template
• Node Learning Notes express, express-template, nodemon
• Node learning notes post, express for comment submission
• Node's Learning Notes Mongodb and Monoose

Reference:

• [Document Node.js v12.13.1]
• [art-template high performance JavaScript template engine]
• [Express - web Application Development Framework Based on Node.js Platform]
• [MongoDB website]
• [Mongoose.js Chinese Web]