How to use the @bentley/config-loader/lib/IModelJsConfig.IModelJsConfig function in @bentley/config-loader

/*---------------------------------------------------------------------------------------------
* Copyright (c) 2019 Bentley Systems, Incorporated. All rights reserved.
* Licensed under the MIT License. See LICENSE.md in the project root for license terms.
*--------------------------------------------------------------------------------------------*/

const path = require("path");
const webpack = require("webpack");
const configLoader = require("@bentley/config-loader/lib/IModelJsConfig")
const configEnv = configLoader.IModelJsConfig.init(true /*suppress error*/, true /* suppress message */);
if (configEnv) {
  Object.assign(process.env, configEnv);
} else {
  console.error("Webpack failed to locate iModelJs configuration");
}


const raw = process.env;
module.exports = {
  mode: "development",
  entry: "./lib/frontend/DisplayPerformanceTestApp.js",
  output: {
    path: path.resolve(__dirname, "./lib/webresources"),
    filename: '[name].bundle.js',
    devtoolModuleFilenameTemplate: "file:///[absolute-resource-path]"
  },

/*---------------------------------------------------------------------------------------------
* Copyright (c) 2019 Bentley Systems, Incorporated. All rights reserved.
* Licensed under the MIT License. See LICENSE.md in the project root for license terms.
*--------------------------------------------------------------------------------------------*/

const path = require("path");
const glob = require("glob");
const webpack = require("webpack");
const raw = require("@bentley/config-loader/lib/IModelJsConfig").IModelJsConfig.init(true /*suppress error*/, true);
module.exports = {
  mode: "development",
  entry: glob.sync(path.resolve(__dirname, "lib/**/*.test.js")),
  output: {
    path: path.resolve(__dirname, "lib/dist"),
    filename: "bundled-tests.js",
    devtoolModuleFilenameTemplate: "file:///[absolute-resource-path]"
  },
  devtool: "nosources-source-map",
  module: {
    noParse: [
      // Don't parse draco_*_nodejs.js modules for `require` calls.  There are
      // requires for fs that cause it to fail even though the fs dependency
      // is not used.
      /draco_decoder_nodejs.js$/,
      /draco_encoder_nodejs.js$/

/*---------------------------------------------------------------------------------------------
* Copyright (c) 2019 Bentley Systems, Incorporated. All rights reserved.
* Licensed under the MIT License. See LICENSE.md in the project root for license terms.
*--------------------------------------------------------------------------------------------*/

const path = require("path");
const glob = require("glob");
const webpack = require("webpack");
const raw = require("@bentley/config-loader/lib/IModelJsConfig").IModelJsConfig.init(true /*suppress error*/, true);

function createConfig(shouldInstrument) {
  const config = {
    mode: "development",
    entry: glob.sync(path.resolve(__dirname, "lib/**/*.test.js")),
    output: {
      path: path.resolve(__dirname, "lib/dist"),
      filename: "bundled-tests.js",
      devtoolModuleFilenameTemplate: "file:///[absolute-resource-path]"
    },
    devtool: "nosources-source-map",
    module: {
      noParse: [
        // Don't parse draco_*_nodejs.js modules for `require` calls.  There are
        // requires for fs that cause it to fail even though the fs dependency
        // is not used.

/*---------------------------------------------------------------------------------------------
* Copyright (c) 2019 Bentley Systems, Incorporated. All rights reserved.
* Licensed under the MIT License. See LICENSE.md in the project root for license terms.
*--------------------------------------------------------------------------------------------*/
"use strict";

const fs = require("fs");
const path = require("path");
const paths = require("./paths");

// Load iModelJS configuration
if (process.env.IMODELJS_USE_CONFIG_LOADER && process.env.IMODELJS_USE_CONFIG_LOADER.toLowerCase() === "yes") {
  const configLoader = require("@bentley/config-loader/lib/IModelJsConfig");
  const configEnv = configLoader.IModelJsConfig.init(false /*suppress error*/);
  if (configEnv && process.env) {
    Object.assign(process.env, configEnv);
  } else {
    console.log("Webpack failed to locate iModelJs configuration");
  }
}

// Make sure that including paths.js after env.js will read .env variables.
delete require.cache[require.resolve("./paths")];

const NODE_ENV = process.env.NODE_ENV;
if (!NODE_ENV) {
  throw new Error(
    "The NODE_ENV environment variable is required but was not specified."
  );
}