Does it mutate 😱

Array.prototype.findIndex

No mutation

Description

The findIndex() method of Array instances returns the index of the first element in an array that satisfies the provided testing function. If no elements satisfy the testing function, -1 is returned.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex

Example

const array1 = [5, 12, 8, 130, 44];

const isLargeNumber = (element) => element > 13;

console.log(array1.findIndex(isLargeNumber));
// Expected output: 3