webpack/lib/CompatibilityPlugin.js

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
var ConstDependency = require("./dependencies/ConstDependency");

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

var jsonLoaderPath = require.resolve("json-loader");
var matchJson = /\.json$/i;

function CompatibilityPlugin() {}
module.exports = CompatibilityPlugin;

CompatibilityPlugin.prototype.apply = function(compiler) {
	compiler.plugin("compilation", function(compilation, params) {
		compilation.dependencyFactories.set(ConstDependency, new NullFactory());
		compilation.dependencyTemplates.set(ConstDependency, new ConstDependency.Template());

		params.normalModuleFactory.plugin("parser", function(parser, parserOptions) {

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

			parser.plugin("call require", function(expr) {
				// support for browserify style require delegator: "require(o, !0)"
				if(expr.arguments.length !== 2) return;
				var second = this.evaluateExpression(expr.arguments[1]);
				if(!second.isBoolean()) return;
				if(second.asBool() !== true) return;
				var dep = new ConstDependency("require", expr.callee.range);
				dep.loc = expr.loc;
				if(this.state.current.dependencies.length > 1) {
					var last = this.state.current.dependencies[this.state.current.dependencies.length - 1];
					if(last.critical && last.request === "." && last.userRequest === "." && last.recursive)
						this.state.current.dependencies.pop();
				}
				this.state.current.addDependency(dep);
				return true;
			});
		});

		params.normalModuleFactory.plugin("after-resolve", function(data, done) {
			// if this is a json file and there are no loaders active, we use the json-loader in order to avoid parse errors
			// @see https://github.com/webpack/webpack/issues/3363
			if(matchJson.test(data.request) && data.loaders.length === 0) {
				data.loaders.push({
					loader: jsonLoaderPath
				});
			}
			done(null, data);
		});
	});
};