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154 lines
4.4 KiB
154 lines
4.4 KiB
4 weeks ago
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/*
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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 memoize = require("../util/memoize");
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const LAZY_TARGET = Symbol("lazy serialization target");
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const LAZY_SERIALIZED_VALUE = Symbol("lazy serialization data");
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/**
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* @template DeserializedType
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* @template SerializedType
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*/
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class SerializerMiddleware {
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/* istanbul ignore next */
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/**
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* @abstract
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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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const AbstractMethodError = require("../AbstractMethodError");
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throw new AbstractMethodError();
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}
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/* istanbul ignore next */
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/**
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* @abstract
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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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const AbstractMethodError = require("../AbstractMethodError");
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throw new AbstractMethodError();
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}
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/**
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* @param {any | function(): Promise<any> | any} value contained value or function to value
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* @param {SerializerMiddleware<any, any>} target target middleware
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* @param {object=} options lazy options
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* @param {any=} serializedValue serialized value
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* @returns {function(): Promise<any> | any} lazy function
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*/
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static createLazy(value, target, options = {}, serializedValue = undefined) {
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if (SerializerMiddleware.isLazy(value, target)) return value;
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const fn = typeof value === "function" ? value : () => value;
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fn[LAZY_TARGET] = target;
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/** @type {any} */ (fn).options = options;
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fn[LAZY_SERIALIZED_VALUE] = serializedValue;
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return fn;
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}
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/**
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* @param {function(): Promise<any> | any} fn lazy function
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* @param {SerializerMiddleware<any, any>=} target target middleware
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* @returns {boolean} true, when fn is a lazy function (optionally of that target)
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*/
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static isLazy(fn, target) {
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if (typeof fn !== "function") return false;
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const t = fn[LAZY_TARGET];
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return target ? t === target : Boolean(t);
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}
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/**
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* @param {function(): Promise<any> | any} fn lazy function
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* @returns {object | undefined} options
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*/
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static getLazyOptions(fn) {
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if (typeof fn !== "function") return;
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return /** @type {any} */ (fn).options;
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}
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/**
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* @param {function(): Promise<any> | any} fn lazy function
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* @returns {any | undefined} serialized value
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*/
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static getLazySerializedValue(fn) {
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if (typeof fn !== "function") return;
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return fn[LAZY_SERIALIZED_VALUE];
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}
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/**
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* @param {function(): Promise<any> | any} fn lazy function
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* @param {any} value serialized value
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* @returns {void}
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*/
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static setLazySerializedValue(fn, value) {
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fn[LAZY_SERIALIZED_VALUE] = value;
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}
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/**
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* @param {function(): Promise<any> | any} lazy lazy function
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* @param {function(any): Promise<any> | any} serialize serialize function
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* @returns {function(): Promise<any> | any} new lazy
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*/
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static serializeLazy(lazy, serialize) {
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const fn = memoize(() => {
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const r = lazy();
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if (r && typeof r.then === "function") {
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return r.then(data => data && serialize(data));
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}
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return serialize(r);
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});
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fn[LAZY_TARGET] = lazy[LAZY_TARGET];
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/** @type {any} */ (fn).options = /** @type {any} */ (lazy).options;
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lazy[LAZY_SERIALIZED_VALUE] = fn;
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return fn;
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}
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/**
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* @param {function(): Promise<any> | any} lazy lazy function
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* @param {function(any): Promise<any> | any} deserialize deserialize function
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* @returns {function(): Promise<any> | any} new lazy
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*/
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static deserializeLazy(lazy, deserialize) {
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const fn = memoize(() => {
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const r = lazy();
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if (r && typeof r.then === "function") {
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return r.then(data => deserialize(data));
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}
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return deserialize(r);
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});
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fn[LAZY_TARGET] = lazy[LAZY_TARGET];
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/** @type {any} */ (fn).options = /** @type {any} */ (lazy).options;
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fn[LAZY_SERIALIZED_VALUE] = lazy;
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return fn;
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}
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/**
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* @param {function(): Promise<any> | any} lazy lazy function
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* @returns {function(): Promise<any> | any} new lazy
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*/
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static unMemoizeLazy(lazy) {
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if (!SerializerMiddleware.isLazy(lazy)) return lazy;
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const fn = () => {
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throw new Error(
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"A lazy value that has been unmemorized can't be called again"
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);
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};
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fn[LAZY_SERIALIZED_VALUE] = SerializerMiddleware.unMemoizeLazy(
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lazy[LAZY_SERIALIZED_VALUE]
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);
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fn[LAZY_TARGET] = lazy[LAZY_TARGET];
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fn.options = /** @type {any} */ (lazy).options;
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return fn;
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}
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}
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module.exports = SerializerMiddleware;
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