webpack/lib/EnvironmentPlugin.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Authors Simen Brekken @simenbrekken, Einar Löve @einarlove
*/

"use strict";

const DefinePlugin = require("./DefinePlugin");
const WebpackError = require("./WebpackError");

/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./DefinePlugin").CodeValue} CodeValue */

class EnvironmentPlugin {
	constructor(...keys) {
		if (keys.length === 1 && Array.isArray(keys[0])) {
			this.keys = keys[0];
			this.defaultValues = {};
		} else if (keys.length === 1 && keys[0] && typeof keys[0] === "object") {
			this.keys = Object.keys(keys[0]);
			this.defaultValues = keys[0];
		} else {
			this.keys = keys;
			this.defaultValues = {};
		}
	}

	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		/** @type {Record<string, CodeValue>} */
		const definitions = {};
		for (const key of this.keys) {
			const value =
				process.env[key] !== undefined
					? process.env[key]
					: this.defaultValues[key];

			if (value === undefined) {
				compiler.hooks.thisCompilation.tap("EnvironmentPlugin", compilation => {
					const error = new WebpackError(
						`EnvironmentPlugin - ${key} environment variable is undefined.\n\n` +
							"You can pass an object with default values to suppress this warning.\n" +
							"See https://webpack.js.org/plugins/environment-plugin for example."
					);

					error.name = "EnvVariableNotDefinedError";
					compilation.errors.push(error);
				});
			}

			definitions[`process.env.${key}`] =
				value === undefined ? "undefined" : JSON.stringify(value);
		}

		new DefinePlugin(definitions).apply(compiler);
	}
}

module.exports = EnvironmentPlugin;