webpack/lib/dependencies/SystemPlugin.js

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
"use strict";

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

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

	apply(compiler) {
		compiler.plugin("compilation", (compilation, params) => {
			params.normalModuleFactory.plugin("parser", (parser, parserOptions) => {

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

				function setNotSupported(name) {
					parser.plugin("evaluate typeof " + name, ParserHelpers.evaluateToString("undefined"));
					parser.plugin("expression " + name,
						ParserHelpers.expressionIsUnsupported(name + " is not supported by webpack.")
					);
				}

				parser.plugin("typeof System", ParserHelpers.toConstantDependency("object"));
				parser.plugin("evaluate typeof System", ParserHelpers.evaluateToString("object"));

				parser.plugin("typeof System.import", ParserHelpers.toConstantDependency("function"));
				parser.plugin("evaluate typeof System.import", ParserHelpers.evaluateToString("function"));

				setNotSupported("System.set");
				setNotSupported("System.get");
				setNotSupported("System.register");
				parser.plugin("expression System", (expr) => {
					const dep = new ConstDependency("{}", expr.range);
					dep.loc = expr.loc;
					parser.state.current.addDependency(dep);
					return true;
				});
			});
		});
	}
}
module.exports = SystemPlugin;