html-webpack-plugin/lib/loader.js

/* This loader renders the template with underscore if no other loader was found */
// @ts-nocheck
"use strict";
const _template = require("lodash/template");

module.exports = function (source) {
  // Get templating options
  const options = this.getOptions();
  const force = options.force || false;

  const allLoadersButThisOne = this.loaders.filter(
    (loader) => loader.normal !== module.exports,
  );

  // This loader shouldn't kick in if there is any other loader (unless it's explicitly enforced)
  if (allLoadersButThisOne.length > 0 && !force) {
    return source;
  }

  // Allow only one html-webpack-plugin loader to allow loader options in the webpack config
  const htmlWebpackPluginLoaders = this.loaders.filter(
    (loader) => loader.normal === module.exports,
  );
  const lastHtmlWebpackPluginLoader =
    htmlWebpackPluginLoaders[htmlWebpackPluginLoaders.length - 1];
  if (this.loaders[this.loaderIndex] !== lastHtmlWebpackPluginLoader) {
    return source;
  }

  // Skip .js files (unless it's explicitly enforced)
  if (/\.(c|m)?js$/.test(this.resourcePath) && !force) {
    return source;
  }

  // The following part renders the template with lodash as a minimalistic loader
  //
  const template = _template(source, {
    interpolate: /<%=([\s\S]+?)%>/g,
    variable: "data",
    ...options,
  });
  // Use `eval("require")("lodash")` to enforce using the native nodejs require
  // during template execution
  return (
    'var _ = eval("require")(' +
    JSON.stringify(require.resolve("lodash")) +
    ");" +
    "module.exports = function (templateParams) { with(templateParams) {" +
    // Execute the lodash template
    "return (" +
    template.source +
    ")();" +
    "}}"
  );
};