498 lines
12 KiB
JavaScript
498 lines
12 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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*/
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"use strict";
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const memorize = require("../util/memorize");
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const ErrorObjectSerializer = require("./ErrorObjectSerializer");
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const MapObjectSerializer = require("./MapObjectSerializer");
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const NullPrototypeObjectSerializer = require("./NullPrototypeObjectSerializer");
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const PlainObjectSerializer = require("./PlainObjectSerializer");
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const RegExpObjectSerializer = require("./RegExpObjectSerializer");
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const SerializerMiddleware = require("./SerializerMiddleware");
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const SetObjectSerializer = require("./SetObjectSerializer");
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/** @typedef {import("./types").ComplexSerializableType} ComplexSerializableType */
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/** @typedef {import("./types").PrimitiveSerializableType} PrimitiveSerializableType */
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/** @typedef {new (...params: any[]) => any} Constructor */
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/*
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Format:
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File -> Section*
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Section -> ObjectSection | ReferenceSection | EscapeSection | OtherSection
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ObjectSection -> ESCAPE (
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number:relativeOffset (number > 0) |
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string:request (string|null):export
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) Section:value* ESCAPE ESCAPE_END_OBJECT
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ReferenceSection -> ESCAPE number:relativeOffset (number < 0)
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EscapeSection -> ESCAPE ESCAPE_ESCAPE_VALUE (escaped value ESCAPE)
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EscapeSection -> ESCAPE ESCAPE_UNDEFINED (escaped value ESCAPE)
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OtherSection -> any (except ESCAPE)
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Why using null as escape value?
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Multiple null values can merged by the BinaryMiddleware, which makes it very efficient
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Technically any value can be used.
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*/
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/**
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* @typedef {Object} ObjectSerializerContext
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* @property {function(any): void} write
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*/
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/**
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* @typedef {Object} ObjectDeserializerContext
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* @property {function(): any} read
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*/
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/**
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* @typedef {Object} ObjectSerializer
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* @property {function(any, ObjectSerializerContext): void} serialize
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* @property {function(ObjectDeserializerContext): any} deserialize
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*/
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const setSetSize = (set, size) => {
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let i = 0;
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for (const item of set) {
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if (i++ >= size) {
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set.delete(item);
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}
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}
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};
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const setMapSize = (map, size) => {
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let i = 0;
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for (const item of map.keys()) {
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if (i++ >= size) {
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map.delete(item);
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}
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}
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};
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const ESCAPE = null;
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const ESCAPE_ESCAPE_VALUE = null;
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const ESCAPE_END_OBJECT = true;
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const ESCAPE_UNDEFINED = false;
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const CURRENT_VERSION = 2;
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const plainObjectSerializer = new PlainObjectSerializer();
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const serializers = new Map();
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const serializerInversed = new Map();
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const loadedRequests = new Set();
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const NOT_SERIALIZABLE = {};
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serializers.set(Object, {
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request: "",
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name: null,
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serializer: plainObjectSerializer
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});
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serializers.set(Array, {
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request: "",
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name: null,
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serializer: plainObjectSerializer
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});
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const jsTypes = new Map();
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jsTypes.set(null, new NullPrototypeObjectSerializer());
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jsTypes.set(Map, new MapObjectSerializer());
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jsTypes.set(Set, new SetObjectSerializer());
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jsTypes.set(RegExp, new RegExpObjectSerializer());
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jsTypes.set(Error, new ErrorObjectSerializer(Error));
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jsTypes.set(EvalError, new ErrorObjectSerializer(EvalError));
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jsTypes.set(RangeError, new ErrorObjectSerializer(RangeError));
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jsTypes.set(ReferenceError, new ErrorObjectSerializer(ReferenceError));
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jsTypes.set(SyntaxError, new ErrorObjectSerializer(SyntaxError));
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jsTypes.set(TypeError, new ErrorObjectSerializer(TypeError));
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{
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let i = 1;
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for (const [type, serializer] of jsTypes) {
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serializers.set(type, {
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request: "",
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name: i++,
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serializer
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});
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}
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}
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for (const { request, name, serializer } of serializers.values()) {
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serializerInversed.set(`${request}/${name}`, serializer);
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}
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/** @type {Map<RegExp, (request: string) => boolean>} */
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const loaders = new Map();
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/**
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* @typedef {ComplexSerializableType[]} DeserializedType
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* @typedef {PrimitiveSerializableType[]} SerializedType
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* @extends {SerializerMiddleware<DeserializedType, SerializedType>}
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*/
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class ObjectMiddleware extends SerializerMiddleware {
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/**
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* @param {RegExp} regExp RegExp for which the request is tested
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* @param {function(string): boolean} loader loader to load the request, returns true when successful
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* @returns {void}
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*/
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static registerLoader(regExp, loader) {
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loaders.set(regExp, loader);
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}
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/**
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* @param {Constructor} Constructor the constructor
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* @param {string} request the request which will be required when deserializing
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* @param {string} name the name to make multiple serializer unique when sharing a request
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* @param {ObjectSerializer} serializer the serializer
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* @returns {void}
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*/
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static register(Constructor, request, name, serializer) {
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const key = request + "/" + name;
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if (serializers.has(Constructor)) {
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throw new Error(
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`ObjectMiddleware.register: serializer for ${Constructor.name} is already registered`
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);
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}
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if (serializerInversed.has(key)) {
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throw new Error(
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`ObjectMiddleware.register: serializer for ${key} is already registered`
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);
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}
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serializers.set(Constructor, {
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request,
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name,
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serializer
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});
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serializerInversed.set(key, serializer);
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}
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/**
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* @param {Constructor} Constructor the constructor
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* @returns {void}
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*/
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static registerNotSerializable(Constructor) {
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if (serializers.has(Constructor)) {
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throw new Error(
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`ObjectMiddleware.registerNotSerializable: serializer for ${Constructor.name} is already registered`
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);
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}
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serializers.set(Constructor, NOT_SERIALIZABLE);
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}
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static getSerializerFor(object) {
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let c = object.constructor;
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if (!c) {
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if (Object.getPrototypeOf(object) === null) {
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// Object created with Object.create(null)
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c = null;
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} else {
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throw new Error(
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"Serialization of objects with prototype without valid constructor property not possible"
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);
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}
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}
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const config = serializers.get(c);
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if (!config) throw new Error(`No serializer registered for ${c.name}`);
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if (config === NOT_SERIALIZABLE) throw NOT_SERIALIZABLE;
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return config;
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}
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static getDeserializerFor(request, name) {
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const key = request + "/" + name;
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const serializer = serializerInversed.get(key);
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if (serializer === undefined) {
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throw new Error(`No deserializer registered for ${key}`);
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}
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return serializer;
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}
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_handleFunctionSerialization(fn, context) {
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return memorize(() => {
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const r = fn();
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if (r instanceof Promise)
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return r.then(data => this.serialize([data], context));
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return this.serialize([r], context);
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});
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}
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_handleFunctionDeserialization(fn, context) {
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return memorize(() => {
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const r = fn();
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if (r instanceof Promise)
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return r.then(data => this.deserialize(data, context)[0]);
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return this.deserialize(r, context)[0];
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});
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}
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/**
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* @param {DeserializedType} data data
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* @param {Object} context context object
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* @returns {SerializedType|Promise<SerializedType>} serialized data
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*/
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serialize(data, context) {
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/** @type {any[]} */
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const result = [CURRENT_VERSION];
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let currentPos = 0;
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const referenceable = new Map();
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const addReferenceable = item => {
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referenceable.set(item, currentPos++);
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};
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let currentPosTypeLookup = 0;
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const objectTypeLookup = new Map();
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const cycleStack = new Set();
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const ctx = {
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write(value) {
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process(value);
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},
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snapshot() {
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return {
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length: result.length,
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cycleStackSize: cycleStack.size,
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referenceableSize: referenceable.size,
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currentPos,
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objectTypeLookupSize: objectTypeLookup.size,
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currentPosTypeLookup
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};
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},
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rollback(snapshot) {
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result.length = snapshot.length;
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setSetSize(cycleStack, snapshot.cycleStackSize);
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setMapSize(referenceable, snapshot.referenceableSize);
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currentPos = snapshot.currentPos;
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setMapSize(objectTypeLookup, snapshot.objectTypeLookupSize);
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currentPosTypeLookup = snapshot.currentPosTypeLookup;
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},
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...context
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};
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const process = item => {
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// check if we can emit a reference
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const ref = referenceable.get(item);
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if (ref !== undefined) {
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result.push(ESCAPE, ref - currentPos);
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return;
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}
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if (Buffer.isBuffer(item)) {
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addReferenceable(item);
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result.push(item);
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} else if (typeof item === "object" && item !== null) {
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if (cycleStack.has(item)) {
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throw new Error(
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`Circular references can't be serialized (${Array.from(cycleStack)
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.concat([item])
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.map(obj => {
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if (obj.constructor === Object)
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return `Object { ${Object.keys(obj).join(", ")} }`;
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return obj.constructor.name;
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})
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.join(" -> ")})`
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);
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}
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const { request, name, serializer } = ObjectMiddleware.getSerializerFor(
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item
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);
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const key = `${request}/${name}`;
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const lastIndex = objectTypeLookup.get(key);
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if (lastIndex === undefined) {
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objectTypeLookup.set(key, currentPosTypeLookup++);
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result.push(ESCAPE, request, name);
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} else {
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result.push(ESCAPE, currentPosTypeLookup - lastIndex);
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}
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cycleStack.add(item);
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serializer.serialize(item, ctx);
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cycleStack.delete(item);
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result.push(ESCAPE, ESCAPE_END_OBJECT);
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addReferenceable(item);
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} else if (typeof item === "string") {
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if (item !== "") {
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// empty strings are shorter when not emitting a reference (this saves 1 byte per empty string)
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addReferenceable(item);
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}
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result.push(item);
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} else if (item === ESCAPE) {
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result.push(ESCAPE, ESCAPE_ESCAPE_VALUE);
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} else if (typeof item === "function") {
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result.push(this._handleFunctionSerialization(item, context));
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} else if (item === undefined) {
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result.push(ESCAPE, ESCAPE_UNDEFINED);
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} else {
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result.push(item);
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}
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};
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try {
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for (const item of data) {
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process(item);
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}
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} catch (e) {
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if (e === NOT_SERIALIZABLE) return null;
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throw e;
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}
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return result;
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}
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/**
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* @param {SerializedType} data data
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* @param {Object} context context object
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* @returns {DeserializedType|Promise<DeserializedType>} deserialized data
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*/
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deserialize(data, context) {
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let currentDataPos = 0;
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const read = () => {
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if (currentDataPos >= data.length)
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throw new Error("Unexpected end of stream");
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return data[currentDataPos++];
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};
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if (read() !== CURRENT_VERSION)
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throw new Error("Version missmatch, serializer changed");
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let currentPos = 0;
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const referenceable = new Map();
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const addReferenceable = item => {
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referenceable.set(currentPos++, item);
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};
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let currentPosTypeLookup = 0;
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const objectTypeLookup = new Map();
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const result = [];
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const ctx = {
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read() {
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return decodeValue();
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},
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...context
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};
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const decodeValue = () => {
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const item = read();
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if (item === ESCAPE) {
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const nextItem = read();
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if (nextItem === ESCAPE_ESCAPE_VALUE) {
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return ESCAPE;
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} else if (nextItem === ESCAPE_UNDEFINED) {
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return undefined;
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} else if (nextItem === ESCAPE_END_OBJECT) {
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throw new Error(
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`Unexpected end of object at position ${currentDataPos - 1}`
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);
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} else if (typeof nextItem === "number" && nextItem < 0) {
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// relative reference
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return referenceable.get(currentPos + nextItem);
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} else {
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const request = nextItem;
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let serializer;
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if (typeof request === "number") {
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serializer = objectTypeLookup.get(currentPosTypeLookup - request);
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} else {
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if (typeof request !== "string") {
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throw new Error(
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`Unexpected type (${typeof request}) of request ` +
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`at position ${currentDataPos - 1}`
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);
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}
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const name = read();
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if (request && !loadedRequests.has(request)) {
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let loaded = false;
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for (const [regExp, loader] of loaders) {
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if (regExp.test(request)) {
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if (loader(request)) {
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loaded = true;
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break;
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}
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}
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}
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if (!loaded) {
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require(request);
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}
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loadedRequests.add(request);
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}
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serializer = ObjectMiddleware.getDeserializerFor(request, name);
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objectTypeLookup.set(currentPosTypeLookup++, serializer);
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}
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const item = serializer.deserialize(ctx);
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const end1 = read();
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if (end1 !== ESCAPE) {
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throw new Error("Expected end of object");
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}
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const end2 = read();
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if (end2 !== ESCAPE_END_OBJECT) {
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throw new Error("Expected end of object");
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}
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addReferenceable(item);
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return item;
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}
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} else if (typeof item === "string") {
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if (item !== "") {
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addReferenceable(item);
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}
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return item;
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} else if (Buffer.isBuffer(item)) {
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addReferenceable(item);
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return item;
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} else if (typeof item === "function") {
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return this._handleFunctionDeserialization(item, context);
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} else {
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return item;
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}
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};
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while (currentDataPos < data.length) {
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result.push(decodeValue());
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}
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return result;
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}
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}
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module.exports = ObjectMiddleware;
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module.exports.NOT_SERIALIZABLE = NOT_SERIALIZABLE;
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