≡ isEq.js -- deep compare objects and arrays in JavaScript
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'use strict';
/**
* ↘️↘️
* @author Muthu Kumar <https://mkr.pw>
* isEq(item1, item2 [, compareKeys])
* @description Deep compares objects or arrays and returns boolean.
* Supports Number, String, Boolean, Regexp, Objects, Arrays
* @param {*} item1 - Object or Array to compare against.
* @param {*} item2 - Object or Array to compare with.
* @param {Array} [compareKeys] - Keys to compare against. Ignores other keys.
*/
const isEq = (item1, item2, compareKeys) => {
// Returns false if different types are used.
if (typeof item1 !== typeof item2) return false;
// Arrays are of type object, hence let's go one further step
// to prove type inequality
if (Array.isArray(item1))
if (!Array.isArray(item2))
return false;
if (Array.isArray(item2))
if (!Array.isArray(item1))
return false;
// Since types are already equal, let's find if items are equal.
if ((typeof item1 === 'number') ||
(typeof item1 === 'string') ||
(typeof item1 === 'boolean') ||
(item1 === null) ||
(item1 === undefined)) {
if (item1 === item2) return true;
else return false;
};
// 'NaN's are special. They aren't equal to each other.
if (item1 === NaN && item2 === NaN) return true;
// Regexp needs to be Stringified first before comparing equality
if (item1 instanceof RegExp) return String(item1) === String(item2);
// If none of the above conditions returned, then check if inputs are handlable
if (typeof (item1) !== 'object' || typeof (item2) !== 'object')
throw new Error('[isEq] Unhandleable input!');
const item1Keys = Object.keys(item1);
const item2Keys = Object.keys(item2);
// If compare keys array is not given, let's check length of props
// and check second array against first.
if (!compareKeys) {
compareKeys = item1Keys;
if (item1Keys.length !== item2Keys.length) {
return false;
};
};
if(!(Array.isArray(compareKeys)))
throw new Error('[isEq] third parameter should be an array of keys!');
// Either both are empty objects or arrays, or compareArray is empty. Return true.
if(compareKeys.length === 0) return true;
// For each key in our reference...
for (let KeyIndex in compareKeys) {
let Key = compareKeys[KeyIndex];
if (Array.isArray(item1[Key]) && Array.isArray(item2[Key])) {
const Key = KeyIndex;
};
// Inequality at this point can be because it's just comparing
// two objects or arrays that may or may not be equivalent.
if (item1[Key] !== item2[Key]) {
if (typeof (item1[Key] === 'object') && typeof (item2[Key] === 'object') ||
(Array.isArray(item1[Key]) && Array.isArray(item2[Key]))) {
if (!isEq(item1[Key], item2[Key])) {
return false;
break;
};
} else {
return false;
break;
};
};
};
return true;
};
module.exports = isEq;