Install:

npm install @jamshop/eleventy-plugin-webpack

In you main config .eleventy.js:

const pluginWebpack = require("@jamshop/eleventy-plugin-webpack");

module.exports = (eleventyConfig) => {
  eleventyConfig.addPlugin(pluginWebpack, {
    entryPoints: {
      main: "src/index.js"
    }
    output: "_site/js",
    configFunction, // A function that recieves a webpack config to modify and return
  });
  // and the rest of your config
};

This will transpile JavaScript insrc/index.js to _site/js/main.js.

Their are 3 main options, entryPoints which is required and should contain a set of key/value pairs. The key represents the output file name (without extensions) and the value is the path to the source file.

The second option output is optional although required in most situations. This is the output directory for the transpiled JavaScript. The generated file path will be a combination of the key and the output.

The third option configFunction allows you to modify the webpack config.