79 lines
2.1 KiB
JavaScript
79 lines
2.1 KiB
JavaScript
/**
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* @fileoverview Serialization utils.
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* @author Bryan Mishkin
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*/
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"use strict";
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/**
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* Check if a value is a primitive or plain object created by the Object constructor.
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* @param {any} val the value to check
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* @returns {boolean} true if so
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* @private
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*/
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function isSerializablePrimitiveOrPlainObject(val) {
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return (
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val === null ||
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typeof val === "string" ||
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typeof val === "boolean" ||
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typeof val === "number" ||
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(typeof val === "object" && val.constructor === Object) ||
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Array.isArray(val)
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);
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}
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/**
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* Check if a value is serializable.
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* Functions or objects like RegExp cannot be serialized by JSON.stringify().
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* Inspired by: https://stackoverflow.com/questions/30579940/reliable-way-to-check-if-objects-is-serializable-in-javascript
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* @param {any} val The value
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* @param {Set<Object>} seenObjects Objects already seen in this path from the root object.
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* @returns {boolean} `true` if the value is serializable
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*/
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function isSerializable(val, seenObjects = new Set()) {
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if (!isSerializablePrimitiveOrPlainObject(val)) {
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return false;
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}
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if (typeof val === "object" && val !== null) {
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if (seenObjects.has(val)) {
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/*
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* Since this is a depth-first traversal, encountering
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* the same object again means there is a circular reference.
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* Objects with circular references are not serializable.
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*/
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return false;
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}
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for (const property in val) {
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if (Object.hasOwn(val, property)) {
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if (!isSerializablePrimitiveOrPlainObject(val[property])) {
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return false;
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}
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if (
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typeof val[property] === "object" &&
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val[property] !== null
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) {
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if (
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/*
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* We're creating a new Set of seen objects because we want to
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* ensure that `val` doesn't appear again in this path, but it can appear
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* in other paths. This allows for resuing objects in the graph, as long as
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* there are no cycles.
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*/
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!isSerializable(
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val[property],
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new Set([...seenObjects, val]),
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)
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) {
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return false;
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}
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}
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}
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}
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}
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return true;
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}
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module.exports = {
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isSerializable,
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};
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