Learning Salesforce Lightning Application Development

Loaders

Loaders allow you to pre-process and transform files as you load them. An example would be converting TypeScript to JavaScript. Let's see an example snippet from the webpack.config.js file:

const path = require('path');const config = {  output: {    filename: 'my-first-webpack.bundle.js'  },  module: {    rules: [      { test: /\.txt$/, use: 'raw-loader' }    ]  }};module.exports = config;

The preceding code snippet tells webpack to process all the text files using a loader named raw-loader, and loads raw UTF-8 content from the file.

Loaders are essentially node modules that is a function like the following one, and the source parameter consists of all the source code as a string:

const loaderUtils = require('loader-utils');module.exports = function ...