What's the best way to check if two JavaScript arrays are identical?

Other Questions JavaScript
1

I’m trying to find an easy way to check if two arrays in JavaScript are the same. I know the basic comparison operator doesn’t work for this. Here’s what I’ve tried:

let fruits1 = ['apple', 'banana', 'orange'];
let fruits2 = ['apple', 'banana', 'orange'];

console.log(fruits1 === fruits2);  // Gives false
console.log(JSON.stringify(fruits1) === JSON.stringify(fruits2));  // Gives true

The JSON method works, but I’m wondering if there’s a faster or more efficient way to do this without going through each item. Any ideas? I just need a simple true or false result. Thanks for any help!

2

I’ve found that using the Array.prototype.toString() method can be a quick and simple way to compare arrays, especially for primitive values. It’s not foolproof for all cases, but it’s worth considering:

function areArraysEqual(arr1, arr2) {
  return arr1.length === arr2.length && arr1.toString() === arr2.toString();
}

This method first checks the length, then converts both arrays to strings and compares them. It’s generally faster than JSON.stringify for small to medium-sized arrays. However, be cautious with objects or nested arrays, as it might not work as expected in those cases. For more complex scenarios, you might need to implement a custom comparison function that suits your specific needs.

3

I’ve dealt with this issue quite a bit in my projects. While the JSON.stringify method works, it can be slow for large arrays. I’ve found that using the every() method combined with Object.is() for a deep comparison is both efficient and reliable. Here’s how I do it:

function arraysAreIdentical(arr1, arr2) {
return arr1.length === arr2.length && arr1.every((value, index) => Object.is(value, arr2[index]));
}

This approach first checks if the arrays have the same length (quick fail if they don’t), then compares each element. It’s faster than JSON.stringify for most cases and handles NaN values correctly. Just be aware that it won’t work for nested arrays or objects - you’d need a recursive function for that. Hope this helps!

4

hey claire, i’ve run into this too. have u tried lodash? its _.isEqual() function is pretty neat for comparing arrays. it’s like:

import _ from 'lodash';
console.log(_.isEqual(fruits1, fruits2));

works great for me, handles nested stuff too. just make sure u dont forget to install lodash first!