How to import jquery using ES6 syntax?

问题

I'm writing a new app using (JavaScript) ES6 syntax through babel transpiler and the preset-es2015 plugins, as well as semantic-ui for the style.

index.js

import * as stylesheet from '../assets/styles/app.scss';
import * as jquery2 from '../dist/scripts/jquery.min';
import * as jquery3 from '../node_modules/jquery/dist/jquery.min';

console.log($('my-app'));

index.html

<!DOCTYPE html>
<html lang="fr">
<head>
<body>
<script src="dist/app.js"></script>
</body>
</html>

Project structure

.
├── app/
│   ├── index.js
├── assets/
├── dist/
│   ├── scripts/
│   │   ├── jquery.min.js
├── index.html
├── node_modules/
│   ├── jquery/
│   │   ├── dist/
│   │   │   ├── jquery.min.js
├── package.json
└── tests/

package.json

  …
  "scripts": {
    "build:app": "browserify -e ./app/index.js -o ./dist/app.js",
    "copy:jquery": "cpy 'node_modules/jquery/dist/jquery.min.js' ./dist/scripts/",
    …
  },
  "devDependencies": {
    "babel-core": "6.3.x",
    "babel-preset-es2015": "6.3.x",
    "babelify": "7.2.x",
    "cpy": "3.4.x",
    "npm-run-all": "1.4.x",
    "sassify": "0.9.x",
    "semantic-ui": "2.1.x",
    …
  },
  "browserify": {
    "transform": [
      [ "babelify", { "presets": [ "es2015"]}],
      [ "sassify", { "auto-inject": true}]
    ]
  }

Question

Using classic <script> tag to import jquery works fine, but I'm trying to use the ES6 syntax.

How do I import jquery to satisfy semantic-ui using ES6 import syntax?
Should I import from the node_modules/ directory or my dist/ (where I copy everything)?

回答1:

index.js

import {$,jQuery} from 'jquery';
// export for others scripts to use
window.$ = $;
window.jQuery = jQuery;

First, as @nem suggested in comment, the import should be done from node_modules/:

Well, importing from dist/ doesn't make sense since that is your distribution folder with production ready app. Building your app should take what's inside node_modules/ and add it to the dist/ folder, jQuery included.

Next, the glob –* as– is wrong as I know what object I'm importing (e.g. jQuery and $), so a straigforward import statement will work.

Last you need to expose it to other scripts using the window.$ = $.

Then, I import as both $ and jQuery to cover all usages, browserify remove import duplication, so no overhead here! ^o^y

回答2:

Based on the solution of Édouard Lopez, but in two lines:

import jQuery from "jquery";
window.$ = window.jQuery = jQuery;

回答3:

You can create a module converter like below:

// jquery.module.js
import 'https://code.jquery.com/jquery-3.3.1.min.js'
export default window.jQuery.noConflict(true)

This will remove global variables introduced by jQuery and export jQuery object as default.

Then use it in your script:

// script.js
import $ from "./jquery.module.js";

$(function(){
  $('body').text('youpi!');
});

Do not forget to load it as a module in your document:

<script type='module' src='./script.js'></script>

http://plnkr.co/edit/a59ETj3Yo2PJ0Aqkxbeu?p=preview

回答4:

Import the entire JQuery's contents in the Global scope. This inserts $ into the current scope, containing all the exported bindings from the JQuery.

import * as $ from 'jquery';

Now the $ belongs to the window object.

回答5:

The accepted answer did not work for me
note : using rollup js dont know if this answer belongs here
after
npm i --save jquery
in custom.js

import {$, jQuery} from 'jquery';

import {jQuery as $} from 'jquery';

i was getting error : Module ...node_modules/jquery/dist/jquery.js does not export jQuery
or
Module ...node_modules/jquery/dist/jquery.js does not export $
rollup.config.js

export default {
    entry: 'source/custom',
    dest: 'dist/custom.min.js',
    plugins: [
        inject({
            include: '**/*.js',
            exclude: 'node_modules/**',
            jQuery: 'jquery',
            // $: 'jquery'
        }),
        nodeResolve({
            jsnext: true,
        }),
        babel(),
        // uglify({}, minify),
    ],
    external: [],
    format: 'iife', //'cjs'
    moduleName: 'mycustom',
};

instead of rollup inject, tried

commonjs({
   namedExports: {
     // left-hand side can be an absolute path, a path
     // relative to the current directory, or the name
     // of a module in node_modules
     // 'node_modules/jquery/dist/jquery.js': [ '$' ]
     // 'node_modules/jquery/dist/jquery.js': [ 'jQuery' ]
        'jQuery': [ '$' ]
},
format: 'cjs' //'iife'
};

package.json

  "devDependencies": {
    "babel-cli": "^6.10.1",
    "babel-core": "^6.10.4",
    "babel-eslint": "6.1.0",
    "babel-loader": "^6.2.4",
    "babel-plugin-external-helpers": "6.18.0",
    "babel-preset-es2015": "^6.9.0",
    "babel-register": "6.9.0",
    "eslint": "2.12.0",
    "eslint-config-airbnb-base": "3.0.1",
    "eslint-plugin-import": "1.8.1",
    "rollup": "0.33.0",
    "rollup-plugin-babel": "2.6.1",
    "rollup-plugin-commonjs": "3.1.0",
    "rollup-plugin-inject": "^2.0.0",
    "rollup-plugin-node-resolve": "2.0.0",
    "rollup-plugin-uglify": "1.0.1",
    "uglify-js": "2.7.0"
  },
  "scripts": {
    "build": "rollup -c",
  },

This worked :
removed the rollup inject and commonjs plugins

import * as jQuery from 'jquery';

then in custom.js

$(function () {
        console.log('Hello jQuery');
});

回答6:

webpack users, add the below to your plugins array.

let plugins = [
  // expose $ and jQuery to global scope.
  new webpack.ProvidePlugin({
    $: 'jquery',
    jQuery: 'jquery'
  })
];

回答7:

If it helps anyone, javascript import statements are hoisted. Thus, if a library has a dependency (eg bootstrap) on jquery in the global namespace (window), this will NOT work:

import {$,jQuery} from 'jquery';
window.$ = $;
window.jQuery = jQuery;
import 'bootstrap/dist/js/bootstrap.min';

This is because the import of bootstrap is hoisted and evaluated before jQuery is attached to window.

One way to get around this is to not import jQuery directly, but instead import a module which itself imports jQuery AND attaches it to the window.

import jQuery from './util/leaked-jquery';
import 'bootstrap/dist/js/bootstrap.min';

where leaked-jquery looks like

import {$,jQuery} from 'jquery';
window.$ = $;
window.jQuery = jQuery;
export default $;
export jQuery;

EG, https://github.com/craigmichaelmartin/weather-app--birch/blob/4d9f3b03719e0a2ea3fb5ddbbfc453a10e9843c6/javascript/util/leak_jquery.js

回答8:

If you are not using any JS build tools/NPM, then you can directly include Jquery as:

import  'https://code.jquery.com/jquery-1.12.4.min.js';
const $ = window.$;

You may skip import(Line 1) if you already included jquery using script tag under head.

回答9:

import {jQuery as $} from 'jquery';

回答10:

I did not see this exact syntax posted yet, and it worked for me in an ES6/Webpack environment:

import $ from "jquery";

Taken directly from jQuery's NPM page. Hope this helps someone.

回答11:

First of all, install and save them in package.json:

npm i --save jquery
npm i --save jquery-ui-dist

Secondly, add a alias in webpack configuration:

resolve: {
  root: [
    path.resolve(__dirname, '../node_modules'),
    path.resolve(__dirname, '../src'),
  ],
  alias: {
    'jquery-ui': 'jquery-ui-dist/jquery-ui.js'
  },
  extensions: ['', '.js', '.json'],
}

It work for me with the last jquery(3.2.1) and jquery-ui(1.12.1).

See my blog for detail: http://code.tonytuan.org/2017/03/webpack-import-jquery-ui-in-es6-syntax.html

回答12:

Import jquery (I installed with 'npm install jquery@1.9.1')

import 'jquery/jquery.js';

Put all your code that depends on jquery inside this method

+function ($) { 
    // your code
}(window.jQuery);

or declare variable $ after import

var $ = window.$

回答13:

I wanted to use the alread-buildy jQuery (from jquery.org) and all the solutions mentioned here didn't work, how I fixed this issue was adding the following lines which should make it work on nearly every environment:

 export default  ( typeof module === 'object' && module.exports && typeof module.exports.noConflict === 'function' )
    ? module.exports.noConflict(true)
    : ( typeof window !== 'undefined' ? window : this ).jQuery.noConflict(true)

回答14:

You can import like this

import("jquery").then((jQuery) => {
  window.$ = jQuery;
  window.jQuery = jQuery;
  import("bootstrap").then((_bs)=>{
    $(function() {});
  })
});

回答15:

My project stack is: ParcelJS + WordPress

WordPress got jQuery v1.12.4 itself and I have also import jQuery v3^ as module for other depending modules as well as bootstrap/js/dist/collapse, for example... Unfortunately, I can’t leave only one jQuery version due to other WordPress modular dependencies. And ofcourse there is conflict arises between two jquery version. Also keep in mind we got two modes for this project running Wordpress(Apache) / ParcelJS (NodeJS), witch make everything little bit difficulty. So at solution for this conflict was searching, sometimes the project broke on the left, sometimes on the right side. SO... My finall solution (I hope it so...) is:

    import $ from 'jquery'
    import 'popper.js'
    import 'bootstrap/js/dist/collapse'
    import 'bootstrap/js/dist/dropdown'
    import 'signalr'

    if (typeof window.$ === 'undefined') {
        window.$ = window.jQ = $.noConflict(true);
    }

    if (process) {
        if (typeof window.jQuery === 'undefined') {
            window.$ = window.jQuery = $.noConflict(true);
        }
    }

    jQ('#some-id').do('something...')    

    /* Other app code continuous below.......... */

I still didn’t understand how myself, but this method works. Errors and conflicts of two jQuery version no longer arise

回答16:

If you are using Webpack 4, the answer is to use the ProvidePlugin. Their documentation specifically covers angular.js with jquery use case:

new webpack.ProvidePlugin({
  'window.jQuery': 'jquery'
});

The issue is that when using import syntax angular.js and jquery will always be imported before you have a chance to assign jquery to window.jQuery (import statements will always run first no matter where they are in the code!). This means that angular will always see window.jQuery as undefined until you use ProvidePlugin.

回答17:

Pika is a CDN that takes care of providing module versions of popular packages

<script type='module'>
    import * as $ from 'https://cdn.skypack.dev/jquery';

    // use it!
    $('#myDev').on('click', alert);
</script>

Skypack is Pika, so you could also use: import * as $ from 'https://cdn.pika.dev/jquery@^3.5.1';

来源：https://stackoverflow.com/questions/63247885/why-import-as-from-jquery-doesnt-work

标签

javascript

jquery

ecmascript-6

browserify

semantic-ui