webpack/lib/dependencies/SystemPlugin.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 WebpackError = require("../WebpackError");

class SystemPlugin {
	constructor(options) {
		this.options = options;
	}

	apply(compiler) {
		compiler.hooks.compilation.tap(
			"SystemPlugin",
			(compilation, { normalModuleFactory }) => {
				const handler = (parser, parserOptions) => {
					if (parserOptions.system !== undefined && !parserOptions.system)
						return;

					const shouldWarn = parserOptions.system === undefined;

					const setNotSupported = name => {
						parser.hooks.evaluateTypeof
							.for(name)
							.tap("SystemPlugin", ParserHelpers.evaluateToString("undefined"));
						parser.hooks.expression
							.for(name)
							.tap(
								"SystemPlugin",
								ParserHelpers.expressionIsUnsupported(
									parser,
									name + " is not supported by webpack."
								)
							);
					};

					parser.hooks.typeof
						.for("System.import")
						.tap(
							"SystemPlugin",
							ParserHelpers.toConstantDependency(
								parser,
								JSON.stringify("function")
							)
						);
					parser.hooks.evaluateTypeof
						.for("System.import")
						.tap("SystemPlugin", ParserHelpers.evaluateToString("function"));
					parser.hooks.typeof
						.for("System")
						.tap(
							"SystemPlugin",
							ParserHelpers.toConstantDependency(
								parser,
								JSON.stringify("object")
							)
						);
					parser.hooks.evaluateTypeof
						.for("System")
						.tap("SystemPlugin", ParserHelpers.evaluateToString("object"));

					setNotSupported("System.set");
					setNotSupported("System.get");
					setNotSupported("System.register");

					parser.hooks.expression.for("System").tap("SystemPlugin", () => {
						const systemPolyfillRequire = ParserHelpers.requireFileAsExpression(
							parser.state.module.context,
							require.resolve("../../buildin/system")
						);
						return ParserHelpers.addParsedVariableToModule(
							parser,
							"System",
							systemPolyfillRequire
						);
					});

					parser.hooks.call.for("System.import").tap("SystemPlugin", expr => {
						if (shouldWarn) {
							parser.state.module.warnings.push(
								new SystemImportDeprecationWarning(
									parser.state.module,
									expr.loc
								)
							);
						}

						return parser.hooks.importCall.call(expr);
					});
				};

				normalModuleFactory.hooks.parser
					.for("javascript/auto")
					.tap("SystemPlugin", handler);
				normalModuleFactory.hooks.parser
					.for("javascript/dynamic")
					.tap("SystemPlugin", handler);
			}
		);
	}
}

class SystemImportDeprecationWarning extends WebpackError {
	constructor(module, loc) {
		super(
			"System.import() is deprecated and will be removed soon. Use import() instead.\n" +
				"For more info visit https://webpack.js.org/guides/code-splitting/"
		);

		this.name = "SystemImportDeprecationWarning";

		this.module = module;
		this.loc = loc;

		Error.captureStackTrace(this, this.constructor);
	}
}

module.exports = SystemPlugin;