使用Webpack 4时如何访问条目文件中的jQuery对象（$）？

Question

I have a very simple Webpack 4 example where I am trying to access the jQuery object in my entry file in order to manipulate the DOM. I have pared it down to what I think is the bare minimum having researched extensively.

I expect the example to set the background color of the body to cyan upon page load. Can't seem to get it to do anything. Looks like the $ variable exposed in the entry file is not the same $ variable in the browser.

UPDATE - PROBLEM SOLVED : I was misusing jQuery below.

Original (defective) entry file ( src/app.js ):

import 'jquery';

$(() => {
  $('body').bgColor = 'cyan';
});

Corrected entry file:

import 'jquery';

$(() => {
  $('body').css('background-color', 'cyan');
});

I use the ProvidePlugin as documented here . Here is my simple webpack.config.js file:

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const webpack = require("webpack");

module.exports = {
  entry: {
    app: './src/app.js',
  },
    output: {
      filename: 'bundle.js',
        path: path.resolve(__dirname, 'dist')
    },
    plugins: [
      new webpack.ProvidePlugin({
        $: 'jquery',
        jQuery: 'jquery'
      }),
      new HtmlWebpackPlugin()
    ],
    devtool: 'inline-source-map'
}

Webpack compiles just fine and the page opens (using webpack-dev-server ), but the background color does not change to cyan as expected. When I log the value of $('body') in the app.js file, I get undefined .

Here is the package.json file:

{
  "name": "foo",
  "version": "1.0.0",
  "description": "",
  "private": true,
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "build": "webpack",
    "start": "webpack-dev-server --inline --open"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "html-webpack-plugin": "^3.2.0",
    "webpack": "^4.16.5",
    "webpack-cli": "^3.1.0",
    "webpack-dev-server": "^3.1.5"
  },
  "dependencies": {
    "jquery": "^3.3.1"
  }
}

Feels like I have a fundamental lack of understanding of how this is supposed to work. Thanks. Your help is greatly appreciated.

Answer 1

Apologies. My mistake on misuse of jQuery. Thanks to @charlietfl for pointing out my mistake in the comments. I used. $('body').bgColor = "cyan" instead of $('body').css('background-color', 'cyan') . Everything else is properly configured. So if you need a simple example, here it is.

I will edit the question and point out my mistake.