webpack/lib/ExternalModuleFactoryDecorator.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, jade, coffee, css, less, ... and your custom stuff.

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

function ExternalModuleFactoryDecorator(factory, type, externals) {
	this.factory = factory;
	this.type = type;
	this.externals = externals;
}
module.exports = ExternalModuleFactoryDecorator;

ExternalModuleFactoryDecorator.prototype.plugin = function() {
	return this.factory.plugin.apply(this.factory, arguments);
};

ExternalModuleFactoryDecorator.prototype.create = function(context, dependency, callback) {
	var factory = this.factory;
	var globalType = this.type;
	function handleExternal(value, type, callback) {
		if(typeof type === "function") {
			callback = type;
			type = undefined;
		}
		if(value === false) return factory.create(context, dependency, callback);
		if(value === true) value = dependency.request;
		if(typeof type === "undefined" && /^[a-z0-9]+ /.test(value)) {
			var idx = value.indexOf(" ");
			type = value.substr(0, idx);
			value = value.substr(idx+1);
		}
		callback(null, new ExternalModule(value, type || globalType));
		return true;
	}
	(function handleExternals(externals, callback) {
		if(typeof externals === "string") {
			if(externals === dependency.request) {
				return handleExternal(dependency.request, callback);
			}
		} else if(Array.isArray(externals)) {
			var i = 0;
			(function next() {
				do {
					var async = true;
					if(i >= externals.length) return callback();
					handleExternals(externals[i++], function(err, module) {
						if(err) return callback(err);
						if(!module) {
							if(async) return async = false;;
							return next();
						}
						callback(null, module);
					});
				} while(!async);
				async = false;
			}());
			return;
		} else if(externals instanceof RegExp) {
			if(externals.test(dependency.request)) {
				return handleExternal(dependency.request, callback);
			}
		} else if(typeof externals === "function") {
			externals.call(null, context, dependency.request, function(err, value, type) {
				if(err) return callback(err);
				if(typeof value !== "undefined") {
					handleExternal(value, type, callback);
				} else {
					callback();
				}
			});
			return;
		} else if(typeof externals === "object" && Object.prototype.hasOwnProperty.call(externals, dependency.request)) {
			return handleExternal(externals[dependency.request], callback);
		}
		callback();
	}(this.externals, function(err, module) {
		if(err) return callback(err);
		if(!module) return handleExternal(false, callback);
		return callback(null, module);
	}));
};