object-deep-recreate/lib/index.js

Re-create deep level changed objects in memory while keeping the same reference for unchanged objects

"use strict";
var __spreadArray = (this && this.__spreadArray) || function (to, from, pack) {
    if (pack || arguments.length === 2) for (var i = 0, l = from.length, ar; i < l; i++) {
        if (ar || !(i in from)) {
            if (!ar) ar = Array.prototype.slice.call(from, 0, i);
            ar[i] = from[i];
        }
    }
    return to.concat(ar || Array.prototype.slice.call(from));
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.appendNewObjectValues = exports.deepRecreate = void 0;
/**
 * Make sure the compared values are of the same type
 * @param newValue - altered in-memory data
 * @param prevValue - cloned snapshot of previous data
 */
function deepRecreate(newValue, prevValue) {
    if (typeof newValue !== typeof prevValue) {
        // comparing different types
        return newValue;
    }
    // for primitive types return new value right away
    if (!newValue || !prevValue || typeof newValue !== 'object')
        return newValue;
    if (Array.isArray(newValue)) {
        if (!Array.isArray(prevValue)) {
            console.warn('Comparing array with non-array');
            return newValue;
        }
        if (JSON.stringify(newValue) === JSON.stringify(prevValue)) {
            return newValue;
        }
        var result_1;
        // check every element if same length
        if (newValue.length === prevValue.length) {
            result_1 = [];
            newValue.forEach(function (v, index) {
                var oldV = prevValue[index];
                result_1.push(deepRecreate(v, oldV));
            });
        }
        else {
            // else removing or adding to array, just create a new instance
            result_1 = __spreadArray([], newValue, true);
        }
        return result_1;
    }
    return appendNewObjectValues(newValue, prevValue);
}
exports.deepRecreate = deepRecreate;
/**
 * @param newObject
 * @param prevObject - cloned snapshot of previous data
 */
function appendNewObjectValues(newObject, prevObject) {
    if (!newObject || JSON.stringify(newObject) === JSON.stringify(prevObject))
        return newObject;
    var result = {};
    Object.keys(newObject).forEach(function (key) {
        var _a, _b;
        var newValue = (_a = newObject) === null || _a === void 0 ? void 0 : _a[key];
        var prevValue = (_b = prevObject) === null || _b === void 0 ? void 0 : _b[key];
        result[key] = deepRecreate(newValue, prevValue);
    });
    return result;
}
exports.appendNewObjectValues = appendNewObjectValues;