Webpack from A to Asia: Webpack import jQuery

Friday, 07/08/2020

Tram Ho

Today’s article I will guide you how to load jQuery into webpack in module load style. If in the old days we had to load jQuery into the web page this way

<span class="token operator">&lt;</span> script src <span class="token operator">=</span> <span class="token string">"jquery.js"</span> <span class="token operator">&gt;</span> <span class="token operator">&lt;</span> <span class="token operator">/</span> script <span class="token operator">&gt;</span>

1 2	<span class="token operator"><</span> script src <span class="token operator">=</span> <span class="token string">"jquery.js"</span> <span class="token operator">></span> <span class="token operator"><</span> <span class="token operator">/</span> script <span class="token operator">></span>

Now with webpack, we don’t do that because it doesn’t suit the trend ^^. Let’s find out how to do it!

1. Prepare the file

Code file original webpack.config.js :

<span class="token keyword">const</span> path <span class="token operator">=</span> <span class="token function">require</span> <span class="token punctuation">(</span> <span class="token string">'path'</span> <span class="token punctuation">)</span>

module <span class="token punctuation">.</span> exports <span class="token operator">=</span> <span class="token punctuation">{</span>
  mode <span class="token operator">:</span> <span class="token string">'development'</span> <span class="token punctuation">,</span>
  entry <span class="token operator">:</span> <span class="token punctuation">{</span>
    main <span class="token operator">:</span> <span class="token punctuation">[</span>
      <span class="token string">'./src/a.js'</span> <span class="token punctuation">,</span>
      <span class="token string">'./src/b.js'</span>
    <span class="token punctuation">]</span>
  <span class="token punctuation">}</span> <span class="token punctuation">,</span>
  output <span class="token operator">:</span> <span class="token punctuation">{</span>
    filename <span class="token operator">:</span> <span class="token string">'[name].js'</span> <span class="token punctuation">,</span>
    path <span class="token operator">:</span> path <span class="token punctuation">.</span> <span class="token function">resolve</span> <span class="token punctuation">(</span> __dirname <span class="token punctuation">,</span> <span class="token string">'dist'</span> <span class="token punctuation">)</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

const path = require ( 'path' )

module . exports = {

mode : 'development' ,

entry : {

main : [

'./src/a.js' ,

'./src/b.js'

]

} ,

output : {

filename : '[name].js' ,

path : path . resolve ( __dirname , 'dist' )

}

File dist/index.html as follows:

<span class="token doctype">&lt;!DOCTYPE html&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span> html</span> <span class="token attr-name">lang</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> en <span class="token punctuation">"</span></span> <span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span> head</span> <span class="token punctuation">&gt;</span></span>
  <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span> meta</span> <span class="token attr-name">charset</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> UTF-8 <span class="token punctuation">"</span></span> <span class="token punctuation">&gt;</span></span>
  <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span> meta</span> <span class="token attr-name">name</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> viewport <span class="token punctuation">"</span></span> <span class="token attr-name">content</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> width=device-width, initial-scale=1.0 <span class="token punctuation">"</span></span> <span class="token punctuation">&gt;</span></span>
  <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span> title</span> <span class="token punctuation">&gt;</span></span> Webpack từ A đến Á cùng kentrung <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span> title</span> <span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span> head</span> <span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span> body</span> <span class="token punctuation">&gt;</span></span>
  <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span> h1</span> <span class="token punctuation">&gt;</span></span> Webpack từ A đến Á cùng kentrung <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span> h1</span> <span class="token punctuation">&gt;</span></span>
  <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span> script</span> <span class="token attr-name">src</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> main.js <span class="token punctuation">"</span></span> <span class="token punctuation">&gt;</span></span> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span> script</span> <span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span> body</span> <span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span> html</span> <span class="token punctuation">&gt;</span></span>

<!DOCTYPE html>

< html lang = " en " >

< head >

< meta charset = " UTF-8 " >

< meta name = " viewport " content = " width=device-width, initial-scale=1.0 " >

< title > Webpack từ A đến Á cùng kentrung </ title >

</ head >

< body >

< h1 > Webpack từ A đến Á cùng kentrung </ h1 >

< script src = " main.js " > </ script >

</ body >

</ html >

We have two files src/a.js and src/b.js Code two js files as follows:

<span class="token function">$</span> <span class="token punctuation">(</span> <span class="token string">'h1'</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">css</span> <span class="token punctuation">(</span> <span class="token string">'color'</span> <span class="token punctuation">,</span> <span class="token string">'white'</span> <span class="token punctuation">)</span>

$ ( 'h1' ) . css ( 'color' , 'white' )

<span class="token function">$</span> <span class="token punctuation">(</span> <span class="token string">'h1'</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">css</span> <span class="token punctuation">(</span> <span class="token string">'background'</span> <span class="token punctuation">,</span> <span class="token string">'purple'</span> <span class="token punctuation">)</span>

$ ( 'h1' ) . css ( 'background' , 'purple' )

The jQuery code above works to find the h1 tag and add a little css in it is also quite simple.

Have not fixed the error, but keep running webpack to see how the results are npm run dev

Open the file dist/index.html and see the h1 tag without adding css, open the log to see the error

Uncaught ReferenceError: $ is not defined at (a.js:1)

1 2	Uncaught ReferenceError: $ is not defined at (a.js:1)

2. Load jQuery for each file

First I have to install jQuery via npm

npm install jquery

1 2	npm install jquery

In this case, we only need the src/a.js file to load jQuery and the other does not. We just need to add jQuery to the correct file.

<span class="token keyword">import</span> $ <span class="token keyword">from</span> <span class="token string">'jquery'</span>

<span class="token function">$</span> <span class="token punctuation">(</span> <span class="token string">'h1'</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">css</span> <span class="token punctuation">(</span> <span class="token string">'color'</span> <span class="token punctuation">,</span> <span class="token string">'white'</span> <span class="token punctuation">)</span>

import $ from 'jquery'

Rerun webpack and we have the following log:

Uncaught ReferenceError: $ is not defined at (b.js:1)

1 2	Uncaught ReferenceError: $ is not defined at (b.js:1)

So in the src/a.js file, I ran the delicious jQuery code but the src/b.js file did not. Still the way above, the file needs to call jQuery is finished.

<span class="token keyword">import</span> $ <span class="token keyword">from</span> <span class="token string">'jquery'</span>

<span class="token function">$</span> <span class="token punctuation">(</span> <span class="token string">'h1'</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">css</span> <span class="token punctuation">(</span> <span class="token string">'background'</span> <span class="token punctuation">,</span> <span class="token string">'purple'</span> <span class="token punctuation">)</span>

import $ from 'jquery'

$ ( 'h1' ) . css ( 'background' , 'purple' )

Rerun webpack and as a result no more errors, css was added successfully.

3. Webpack Provide Plugin

With the way on any file need to call jQuery in, quite a lot of writing. We have a second way to provide a webpack plugin to dynamically load jQuery, we just need to point both variables that it displays to the respective button module:

<span class="token keyword">const</span> path <span class="token operator">=</span> <span class="token function">require</span> <span class="token punctuation">(</span> <span class="token string">'path'</span> <span class="token punctuation">)</span>
<span class="token keyword">const</span> webpack <span class="token operator">=</span> <span class="token function">require</span> <span class="token punctuation">(</span> <span class="token string">'webpack'</span> <span class="token punctuation">)</span>

module <span class="token punctuation">.</span> exports <span class="token operator">=</span> <span class="token punctuation">{</span>
  mode <span class="token operator">:</span> <span class="token string">'development'</span> <span class="token punctuation">,</span>
  entry <span class="token operator">:</span> <span class="token punctuation">{</span>
    main <span class="token operator">:</span> <span class="token punctuation">[</span>
      <span class="token string">'./src/a.js'</span> <span class="token punctuation">,</span>
      <span class="token string">'./src/b.js'</span>
    <span class="token punctuation">]</span>
  <span class="token punctuation">}</span> <span class="token punctuation">,</span>
  output <span class="token operator">:</span> <span class="token punctuation">{</span>
    filename <span class="token operator">:</span> <span class="token string">'[name].js'</span> <span class="token punctuation">,</span>
    path <span class="token operator">:</span> path <span class="token punctuation">.</span> <span class="token function">resolve</span> <span class="token punctuation">(</span> __dirname <span class="token punctuation">,</span> <span class="token string">'dist'</span> <span class="token punctuation">)</span>
  <span class="token punctuation">}</span> <span class="token punctuation">,</span>
  plugins <span class="token operator">:</span> <span class="token punctuation">[</span>
    <span class="token keyword">new</span> <span class="token class-name">webpack <span class="token punctuation">.</span> ProvidePlugin</span> <span class="token punctuation">(</span> <span class="token punctuation">{</span>
      $ <span class="token operator">:</span> <span class="token string">'jquery'</span> <span class="token punctuation">,</span>
      jQuery <span class="token operator">:</span> <span class="token string">'jquery'</span>
    <span class="token punctuation">}</span> <span class="token punctuation">)</span>
  <span class="token punctuation">]</span>
<span class="token punctuation">}</span>

const webpack = require ( 'webpack' )

module . exports = {

mode : 'development' ,

entry : {

main : [

'./src/a.js' ,

'./src/b.js'

]

} ,

output : {

filename : '[name].js' ,

} ,

plugins : [

new webpack . ProvidePlugin ( {

$ : 'jquery' ,

jQuery : 'jquery'

} )

]

}

Now the two js files keep jQuery code rumbling without having to import anything

<span class="token function">$</span> <span class="token punctuation">(</span> <span class="token string">'h1'</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">css</span> <span class="token punctuation">(</span> <span class="token string">'color'</span> <span class="token punctuation">,</span> <span class="token string">'white'</span> <span class="token punctuation">)</span>

<span class="token function">$</span> <span class="token punctuation">(</span> <span class="token string">'h1'</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">css</span> <span class="token punctuation">(</span> <span class="token string">'background'</span> <span class="token punctuation">,</span> <span class="token string">'purple'</span> <span class="token punctuation">)</span>

$ ( 'h1' ) . css ( 'background' , 'purple' )

Now run webpack again: npm run dev and as a result, css has been added correctly as desired. That’s it, we no longer have to manually load jQuery as before, we all have webpack to take care of you just code ^^!

This article is over, hopefully with this article you have added a lot of useful knowledge. See you in the next article!

More information at: https://webpack.js.org/plugins/provide-plugin/#usage-jquery
Sourcode github: https://github.com/kentrung/webpack-tutorial

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Source : Viblo

Webpack from A to Asia: Webpack import jQuery

1. Prepare the file

2. Load jQuery for each file

3. Webpack Provide Plugin

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