getAsyncWeakSource(dependencies, id, { chunkGraph, runtimeTemplate }) {
		const arrow = runtimeTemplate.supportsArrowFunction();
		const map = this.getUserRequestMap(dependencies, chunkGraph);
		const fakeMap = this.getFakeMap(dependencies, chunkGraph);
		const returnModuleObject = this.getReturnModuleObjectSource(fakeMap, true);

		return `var map = ${JSON.stringify(map, null, "\t")};
${this.getFakeMapInitStatement(fakeMap)}

function webpackAsyncContext(req) {
	return webpackAsyncContextResolve(req).then(${
		arrow ? "id =>" : "function(id)"
	} {
		if(!${RuntimeGlobals.moduleFactories}[id]) {
			var e = new Error("Module '" + req + "' ('" + id + "') is not available (weak dependency)");
			e.code = 'MODULE_NOT_FOUND';
			throw e;
		}
		${returnModuleObject}
	});
}
function webpackAsyncContextResolve(req) {
	// Here Promise.resolve().then() is used instead of new Promise() to prevent
	// uncaught exception popping up in devtools
	return Promise.resolve().then(${arrow ? "() =>" : "function()"} {
		if(!${RuntimeGlobals.hasOwnProperty}(map, req)) {
			var e = new Error("Cannot find module '" + req + "'");
			e.code = 'MODULE_NOT_FOUND';
			throw e;
		}
		return map[req];
	});
}
webpackAsyncContext.keys = ${runtimeTemplate.returningFunction(
			"Object.keys(map)"
		)};
webpackAsyncContext.resolve = webpackAsyncContextResolve;
webpackAsyncContext.id = ${JSON.stringify(id)};
module.exports = webpackAsyncContext;`;
	}
@param {Dependency[]} dependencies dependencies
@param {ModuleId} id module id
@param {object} context context
@param {ChunkGraph} context.chunkGraph the chunk graph
@param {RuntimeTemplate} context.runtimeTemplate the chunk graph
@returns {string} source code