allow serializing of objects with null prototype

lib/serialization/NullPrototypeObjectSerializer.js

@@ -0,0 +1,33 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+*/
+
+"use strict";
+
+class NullPrototypeObjectSerializer {
+	serialize(obj, { write }) {
+		const keys = Object.keys(obj);
+		for (const key of keys) {
+			write(key);
+		}
+		write(null);
+		for (const key of keys) {
+			write(obj[key]);
+		}
+	}
+	deserialize({ read }) {
+		const obj = Object.create(null);
+		const keys = [];
+		let key = read();
+		while (key !== null) {
+			keys.push(key);
+			key = read();
+		}
+		for (const key of keys) {
+			obj[key] = read();
+		}
+		return obj;
+	}
+}
+
+module.exports = NullPrototypeObjectSerializer;

lib/serialization/ObjectMiddleware.js

@@ -7,6 +7,7 @@
 const memorize = require("../util/memorize");
 const ErrorObjectSerializer = require("./ErrorObjectSerializer");
 const MapObjectSerializer = require("./MapObjectSerializer");
+const NullPrototypeObjectSerializer = require("./NullPrototypeObjectSerializer");
 const PlainObjectSerializer = require("./PlainObjectSerializer");
 const RegExpObjectSerializer = require("./RegExpObjectSerializer");
 const SerializerMiddleware = require("./SerializerMiddleware");
@@ -75,7 +76,7 @@ const ESCAPE_ESCAPE_VALUE = null;
 const ESCAPE_END_OBJECT = true;
 const ESCAPE_UNDEFINED = false;
 
-const CURRENT_VERSION = 1;
+const CURRENT_VERSION = 2;
 
 const plainObjectSerializer = new PlainObjectSerializer();
 
@@ -99,6 +100,7 @@ serializers.set(Array, {
 });
 
 const jsTypes = new Map();
+jsTypes.set(null, new NullPrototypeObjectSerializer());
 jsTypes.set(Map, new MapObjectSerializer());
 jsTypes.set(Set, new SetObjectSerializer());
 jsTypes.set(RegExp, new RegExpObjectSerializer());
@@ -187,7 +189,17 @@ class ObjectMiddleware extends SerializerMiddleware {
 	}
 
 	static getSerializerFor(object) {
-		const c = object.constructor;
+		let c = object.constructor;
+		if (!c) {
+			if (Object.getPrototypeOf(object) === null) {
+				// Object created with Object.create(null)
+				c = null;
+			} else {
+				throw new Error(
+					"Serialization of objects with prototype without valid constructor property not possible"
+				);
+			}
+		}
 		const config = serializers.get(c);
 
 		if (!config) throw new Error(`No serializer registered for ${c.name}`);

test/cases/loaders/emit-file/file.js

@@ -0,0 +1 @@
+module.exports = "ok";

test/cases/loaders/emit-file/index.js

@@ -0,0 +1,6 @@
+import "./loader!./file";
+
+it("should have the file emitted", () => {
+	const result = __non_webpack_require__("./extra-file.js");
+	expect(result).toBe("ok");
+});

test/cases/loaders/emit-file/loader.js

@@ -0,0 +1,4 @@
+module.exports = function(content) {
+	this.emitFile("extra-file.js", content);
+	return "";
+}