Detailed explanation of using webpack hot module replacement
This time I will bring you a detailed explanation of the use of webpack hot module replacement. What are the precautions when using webpack hot module replacement. The following is a practical case, let's take a look.
The function of hot module replacement (HMR) is that when the application is running, necessary modules can be replaced, added, and deleted without refreshing the page. This article mainly introduces webpack hot module replacement (HMR)/ The editor thinks the hot update method is quite good, so I would like to share it with you now and give it as a reference. Let’s follow the editor and take a look.
This is an article about the simplest configuration of webpack hot module replacement (react is not required), also called hot update.
The function of hot module replacement (HMR) is to replace, add, and delete necessary modules without refreshing the page when the application is running. HMR is useful for applications that consist of a single state tree. Because the components of these applications are "dumb" (as opposed to "smart"), after the component's code changes, the state of the component can still correctly reflect the latest state of the application.
webpack-dev-server has built-in "live reload", which will automatically refresh the page.
The file directory is as follows:
app
- ##a.js
- component.js
- index.js
- node_modules
- package.json
- webpack.config.js ##a.js is imported into component.js. index.js imports component.js. Modifying any file can achieve the hot update function.
The most important thing is that in index.js, there is such a piece of code: (Required to complete hot update)
if(module.hot){
module.hot.accept(moduleId, callback);
}The following is the package.json configuration:
{
"name": "webpack-hmr",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "nodemon --watch webpack.config.js --exec \"webpack-dev-server --env development\"",
"build": "webpack --env production"
},
"keywords": [],
"author": "",
"license": "ISC",
"devDependencies": {
"html-webpack-plugin": "^2.28.0",
"nodemon": "^1.11.0",
"webpack": "^2.2.1",
"webpack-dev-server": "^2.4.1"
}
}As you can see from the dependencies, this is really the simplest configuration. Among them, nodemon is used to monitor the status of the webpack.config.js file. As long as there is a change, the command will be re-executed.
Regarding "html-webpack-plugin", it can be omitted here. For specific configuration, please see:
https://www.npmjs.com/package/html-webpack-plugin. Here, two commands are defined, one is start, used in the development environment; the other is build, used in the production environment. --watch is used to monitor one or more files, and --exec is used by nodemon to execute other commands. For specific configuration, please see: https://c9.io/remy/nodemon.
The next step is webpack.config.js. Since two commands are defined in the scripts of package.json, we still have to implement two situations (development and production) in the
config file , you can also modify the configuration of one of them). const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const webpack = require('webpack');
const PATHS = {
app: path.join(dirname, 'app'),
build: path.join(dirname, 'build'),
};
const commonConfig={
entry: {
app: PATHS.app + '/index.js',
},
output: {
path: PATHS.build,
filename: '[name].js',
},
watch: true,
plugins: [
new HtmlWebpackPlugin({
title: 'Webpack demo',
}),
],
}
function developmentConfig(){
const config ={
devServer:{
historyApiFallback:true, //404s fallback to ./index.html
// hotOnly:true, 使用hotOnly和hot都可以
hot: true,
stats:'errors-only', //只在发生错误时输出
// host:process.env.Host, 这里是undefined，参考的别人文章有这个
// port:process.env.PORT, 这里是undefined，参考的别人文章有这个
overlay:{ //当有编译错误或者警告的时候显示一个全屏overlay
errors:true,
warnings:true,
}
},
plugins: [
new webpack.HotModuleReplacementPlugin(),
new webpack.NamedModulesPlugin(), // 更新组件时在控制台输出组件的路径而不是数字ID，用在开发模式
// new webpack.HashedModuleIdsPlugin(), // 用在生产模式
],
};
return Object.assign(
{},
commonConfig,
config,
{
plugins: commonConfig.plugins.concat(config.plugins),
}
);
}
module.exports = function(env){
console.log("env",env);
if(env=='development'){
return developmentConfig();
}
return commonConfig;
};
The env parameter is passed in through cli.
Then open the command line to the current directory and run npm start or npm run build. Note that the former is in the development environment and has no output file (in memory). Only when the latter is run will there be an output file.
The code of the demo is at: https://github.com/yuwanlin/webpackHMR
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website !
Recommended reading:
How to choose the jQuery version
##Detailed explanation of using mint-ui in vue
The above is the detailed content of Detailed explanation of using webpack hot module replacement. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1657
14
1415
52
1309
25
1257
29
1230
24
Detailed explanation of obtaining administrator rights in Win11
Mar 08, 2024 pm 03:06 PM
Windows operating system is one of the most popular operating systems in the world, and its new version Win11 has attracted much attention. In the Win11 system, obtaining administrator rights is an important operation. Administrator rights allow users to perform more operations and settings on the system. This article will introduce in detail how to obtain administrator permissions in Win11 system and how to effectively manage permissions. In the Win11 system, administrator rights are divided into two types: local administrator and domain administrator. A local administrator has full administrative rights to the local computer
Detailed explanation of division operation in Oracle SQL
Mar 10, 2024 am 09:51 AM
Detailed explanation of division operation in OracleSQL In OracleSQL, division operation is a common and important mathematical operation, used to calculate the result of dividing two numbers. Division is often used in database queries, so understanding the division operation and its usage in OracleSQL is one of the essential skills for database developers. This article will discuss the relevant knowledge of division operations in OracleSQL in detail and provide specific code examples for readers' reference. 1. Division operation in OracleSQL
Detailed explanation of the linux system call system() function
Feb 22, 2024 pm 08:21 PM
Detailed explanation of Linux system call system() function System call is a very important part of the Linux operating system. It provides a way to interact with the system kernel. Among them, the system() function is one of the commonly used system call functions. This article will introduce the use of the system() function in detail and provide corresponding code examples. Basic Concepts of System Calls System calls are a way for user programs to interact with the operating system kernel. User programs request the operating system by calling system call functions
Detailed explanation of the role and usage of PHP modulo operator
Mar 19, 2024 pm 04:33 PM
The modulo operator (%) in PHP is used to obtain the remainder of the division of two numbers. In this article, we will discuss the role and usage of the modulo operator in detail, and provide specific code examples to help readers better understand. 1. The role of the modulo operator In mathematics, when we divide an integer by another integer, we get a quotient and a remainder. For example, when we divide 10 by 3, the quotient is 3 and the remainder is 1. The modulo operator is used to obtain this remainder. 2. Usage of the modulo operator In PHP, use the % symbol to represent the modulus
Detailed explanation of Linux curl command
Feb 21, 2024 pm 10:33 PM
Detailed explanation of Linux's curl command Summary: curl is a powerful command line tool used for data communication with the server. This article will introduce the basic usage of the curl command and provide actual code examples to help readers better understand and apply the command. 1. What is curl? curl is a command line tool used to send and receive various network requests. It supports multiple protocols, such as HTTP, FTP, TELNET, etc., and provides rich functions, such as file upload, file download, data transmission, proxy
Learn more about Promise.resolve()
Feb 18, 2024 pm 07:13 PM
Detailed explanation of Promise.resolve() requires specific code examples. Promise is a mechanism in JavaScript for handling asynchronous operations. In actual development, it is often necessary to handle some asynchronous tasks that need to be executed in sequence, and the Promise.resolve() method is used to return a Promise object that has been fulfilled. Promise.resolve() is a static method of the Promise class, which accepts a
How to enable administrative access from the cockpit web UI
Mar 20, 2024 pm 06:56 PM
Cockpit is a web-based graphical interface for Linux servers. It is mainly intended to make managing Linux servers easier for new/expert users. In this article, we will discuss Cockpit access modes and how to switch administrative access to Cockpit from CockpitWebUI. Content Topics: Cockpit Entry Modes Finding the Current Cockpit Access Mode Enable Administrative Access for Cockpit from CockpitWebUI Disabling Administrative Access for Cockpit from CockpitWebUI Conclusion Cockpit Entry Modes The cockpit has two access modes: Restricted Access: This is the default for the cockpit access mode. In this access mode you cannot access the web user from the cockpit
Detailed explanation of numpy version query method
Jan 19, 2024 am 08:20 AM
Numpy is a Python scientific computing library that provides a wealth of array operation functions and tools. When upgrading the Numpy version, you need to query the current version to ensure compatibility. This article will introduce the method of Numpy version query in detail and provide specific code examples. Method 1: Use Python code to query the Numpy version. You can easily query the Numpy version using Python code. The following is the implementation method and sample code: importnumpyasnpprint(np
