webpack/lib/ProvidePlugin.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
	Author Tobias Koppers @sokra
*/
"use strict";

const ParserHelpers = require("./ParserHelpers");
const ConstDependency = require("./dependencies/ConstDependency");

const NullFactory = require("./NullFactory");

class ProvidePlugin {
	constructor(definitions) {
		this.definitions = definitions;
	}

	apply(compiler) {
		const definitions = this.definitions;
		compiler.hooks.compilation.tap(
			"ProvidePlugin",
			(compilation, { normalModuleFactory }) => {
				compilation.dependencyFactories.set(ConstDependency, new NullFactory());
				compilation.dependencyTemplates.set(
					ConstDependency,
					new ConstDependency.Template()
				);
				const handler = (parser, parserOptions) => {
					Object.keys(definitions).forEach(name => {
						var request = [].concat(definitions[name]);
						var splittedName = name.split(".");
						if (splittedName.length > 0) {
							splittedName.slice(1).forEach((_, i) => {
								const name = splittedName.slice(0, i + 1).join(".");
								parser.hooks.canRename
									.for(name)
									.tap("ProvidePlugin", ParserHelpers.approve);
							});
						}
						parser.hooks.expression.for(name).tap("ProvidePlugin", expr => {
							let nameIdentifier = name;
							const scopedName = name.includes(".");
							let expression = `require(${JSON.stringify(request[0])})`;
							if (scopedName) {
								nameIdentifier = `__webpack_provided_${name.replace(
									/\./g,
									"_dot_"
								)}`;
							}
							if (request.length > 1) {
								expression += request
									.slice(1)
									.map(r => `[${JSON.stringify(r)}]`)
									.join("");
							}
							if (
								!ParserHelpers.addParsedVariableToModule(
									parser,
									nameIdentifier,
									expression
								)
							) {
								return false;
							}
							if (scopedName) {
								ParserHelpers.toConstantDependency(parser, nameIdentifier)(
									expr
								);
							}
							return true;
						});
					});
				};
				normalModuleFactory.hooks.parser
					.for("javascript/auto")
					.tap("ProvidePlugin", handler);
				normalModuleFactory.hooks.parser
					.for("javascript/dynamic")
					.tap("ProvidePlugin", handler);

				// Disable ProvidePlugin for javascript/esm, see https://github.com/webpack/webpack/issues/7032
			}
		);
	}
}
module.exports = ProvidePlugin;