How to use the @rails/webpacker.merge function in @rails/webpacker

/* eslint-disable */

const { webpackConfig, merge } = require("@rails/webpacker")
const customConfig = require("./custom")

module.exports = merge(webpackConfig, customConfig)

/* eslint-disable */

const { webpackConfig, merge } = require("@rails/webpacker")
const customConfig = require("./custom")

module.exports = merge(webpackConfig, customConfig)

process.env.NODE_ENV = process.env.NODE_ENV || 'development'

const { merge } = require('@rails/webpacker')
const webpackConfig = require('./base');
const ESLintPlugin = require('eslint-webpack-plugin');

module.exports = merge(webpackConfig, {
  plugins: [
    new ESLintPlugin({
      cache: true,
      threads: true,
      emitWarning: true
    })
  ]
});

const commonWebpackConfig = () =>
  merge({}, baseClientWebpackConfig, commonOptions)

const { webpackConfig, merge } = require('@rails/webpacker')

module.exports = merge(webpackConfig, {
  output: {
    library: "Danbooru",
  },
  resolve: {
    alias: {
      "jquery": "jquery/src/jquery.js",
      "react": "preact/compat",
      "react-dom": "preact/compat",
    }
  },
  module: {
    rules: [{
      test: /.erb$/,
      enforce: "pre",
      exclude: /node_modules/,
      loader: "rails-erb-loader",