webpack/lib/dependencies/SystemPlugin.js

/*
	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(typeof parserOptions.system !== "undefined" && !parserOptions.system)
					return;

				const shouldWarn = typeof 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.js"));
					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();

		this.name = "SystemImportDeprecationWarning";
		this.message = "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.origin = this.module = module;
		this.originLoc = loc;

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

module.exports = SystemPlugin;