modify-config-helper.ts

import chalk from "chalk";
import * as fs from "fs";
import * as logSymbols from "log-symbols";
import * as path from "path";
import * as yeoman from "yeoman-environment";
import * as Generator from "yeoman-generator";


import runTransform from "./scaffold";

export interface Config extends Object {
	item?: {
		name: string;
	};
	topScope?: string[];
	configName?: string;
	merge: string|string[];
	webpackOptions: object;
}

export interface TransformConfig extends Object {
	configPath?: string;
	configFile?: string;
	config?: Config;
}

const DEFAULT_WEBPACK_CONFIG_FILENAME = "webpack.config.js";

/**
 *
 * Looks up the webpack.config in the user's path and runs a given
 * generator scaffold followed up by a transform
 *
 * @param {String} action — action to be done (add, remove, update, init)
 * @param {Class} generator - Yeoman generator class
 * @param {String} configFile - Name of the existing/default webpack configuration file
 * @param {Array} packages - List of packages to resolve
 * @returns {Function} runTransform - Returns a transformation instance
 */

export default function modifyHelperUtil(
	action: string,
	generator: typeof Generator,
	configFile: string = DEFAULT_WEBPACK_CONFIG_FILENAME,
	packages?: string[]
): typeof Generator {
	let configPath: string | null = null;

	if (action !== "init") {
		configPath = path.resolve(process.cwd(), configFile);
		const webpackConfigExists: boolean = fs.existsSync(configPath);
		if (webpackConfigExists) {
			process.stdout.write(
				"\n" +
					logSymbols.success +
					chalk.green(" SUCCESS ") +
					"Found config " +
					chalk.cyan(configFile + "\n") +
					"\n"
			);
		} else {
			process.stdout.write(
				"\n" +
					logSymbols.error +
					chalk.red(" ERROR ") +
					chalk.cyan(configFile) +
					" not found. Please specify a valid path to your webpack config like \n " +
					chalk.white("$ ") +
					chalk.cyan(`webpack-cli ${action} webpack.dev.js`) +
					"\n"
			);
			return;
		}
	}

	const env = yeoman.createEnv("webpack", null);
	const generatorName = `webpack-${action}-generator`;

	if (!generator) {
		generator = class extends Generator {
			public initializing(): void {
				packages.forEach(
					(pkgPath: string): Generator => {
						return this.composeWith(require.resolve(pkgPath), {});
					}
				);
			}
		};
	}
	
	env.registerStub(generator, generatorName);
	env.run(generatorName, {
		configFile
	}).then(
			(): void => {
				let configModule: object;
				try {
					const confPath = path.resolve(process.cwd(), ".yo-rc.json");
					configModule = require(confPath);
					// Change structure of the config to be transformed
					const tmpConfig: object = {};
					Object.keys(configModule).forEach(
						(prop: string): void => {
							const configs = Object.keys(configModule[prop].configuration);
							configs.forEach(
								(conf: string): void => {
									tmpConfig[conf] = configModule[prop].configuration[conf];
								}
							);
						}
					);
					configModule = tmpConfig;
				} catch (err) {
					console.error(chalk.red("\nCould not find a yeoman configuration file.\n"));
					console.error(
						chalk.red(
							"\nPlease make sure to use 'this.config.set('configuration', this.configuration);' at the end of the generator.\n"
						)
					);
					Error.stackTraceLimit = 0;
					process.exitCode = -1;
				}
				const transformConfig: TransformConfig = Object.assign(
					{
						configFile: !configPath ? null : fs.readFileSync(configPath, "utf8"),
						configPath
					},
					configModule
				);
				return runTransform(transformConfig, action);
			}
		)
		.catch(
			(err): void => {
				console.error(
					chalk.red(
						`
Unexpected Error
please file an issue here https://github.com/webpack/webpack-cli/issues/new?template=Bug_report.md
				`
					)
				);
				console.error(err);
			}
		);
}