speed-measure-webpack-plugin/loader.js

const path = require("path");
const fs = require("fs");
const { hackWrapLoaders } = require("./utils");

let id = 0;

const NS = path.dirname(fs.realpathSync(__filename));

const getLoaderName = path => {
  const nodeModuleName = /\/node_modules\/([^\/]+)/.exec(path);
  return (nodeModuleName && nodeModuleName[1]) || "";
};

module.exports.pitch = function() {
  const callback = this[NS];
  const module = this.resourcePath;
  const loaderPaths = this.loaders
    .map(l => l.path)
    .filter(l => !l.includes("speed-measure-webpack-plugin"));

  // Hack ourselves to overwrite the `require` method so we can override the
  // loadLoaders
  hackWrapLoaders(loaderPaths, (loader, path) => {
    const loaderName = getLoaderName(path);
    const wrapFunc = func =>
      function() {
        const loaderId = id++;
        const almostThis = Object.assign({}, this, {
          async: function() {
            const asyncCallback = this.async.apply(this, arguments);

            return function() {
              callback({
                id: loaderId,
                type: "end",
              });
              return asyncCallback.apply(this, arguments);
            };
          }.bind(this)
        });

        callback({
          module,
          loaderName,
          id: loaderId,
          type: "start",
        });
        const ret = func.apply(almostThis, arguments);
        callback({
          id: loaderId,
          type: "end",
        });
        return ret;
      };

    if (loader.normal) loader.normal = wrapFunc(loader.normal);
    if (loader.default) loader.default = wrapFunc(loader.default);
    if (loader.pitch) loader.pitch = wrapFunc(loader.pitch);
    if (typeof loader === "function") return wrapFunc(loader);
    return loader;
  });
};