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- /*
- MIT License http://www.opensource.org/licenses/mit-license.php
- */
- "use strict";
- /** @typedef {import("./ObjectMiddleware").ObjectDeserializerContext} ObjectDeserializerContext */
- /** @typedef {import("./ObjectMiddleware").ObjectSerializerContext} ObjectSerializerContext */
- const cache = new WeakMap();
- class ObjectStructure {
- constructor() {
- this.keys = undefined;
- this.children = undefined;
- }
- getKeys(keys) {
- if (this.keys === undefined) this.keys = keys;
- return this.keys;
- }
- key(key) {
- if (this.children === undefined) this.children = new Map();
- const child = this.children.get(key);
- if (child !== undefined) return child;
- const newChild = new ObjectStructure();
- this.children.set(key, newChild);
- return newChild;
- }
- }
- const getCachedKeys = (keys, cacheAssoc) => {
- let root = cache.get(cacheAssoc);
- if (root === undefined) {
- root = new ObjectStructure();
- cache.set(cacheAssoc, root);
- }
- let current = root;
- for (const key of keys) {
- current = current.key(key);
- }
- return current.getKeys(keys);
- };
- class PlainObjectSerializer {
- /**
- * @param {object} obj plain object
- * @param {ObjectSerializerContext} context context
- */
- serialize(obj, context) {
- const keys = Object.keys(obj);
- if (keys.length > 128) {
- // Objects with so many keys are unlikely to share structure
- // with other objects
- context.write(keys);
- for (const key of keys) {
- context.write(obj[key]);
- }
- } else if (keys.length > 1) {
- context.write(getCachedKeys(keys, context.write));
- for (const key of keys) {
- context.write(obj[key]);
- }
- } else if (keys.length === 1) {
- const key = keys[0];
- context.write(key);
- context.write(obj[key]);
- } else {
- context.write(null);
- }
- }
- /**
- * @param {ObjectDeserializerContext} context context
- * @returns {object} plain object
- */
- deserialize(context) {
- const keys = context.read();
- const obj = {};
- if (Array.isArray(keys)) {
- for (const key of keys) {
- obj[key] = context.read();
- }
- } else if (keys !== null) {
- obj[keys] = context.read();
- }
- return obj;
- }
- }
- module.exports = PlainObjectSerializer;
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