Mastering JavaScript Functional Programming - Second Edition

Searching an array

Sometimes, instead of filtering all the elements of an array, you want to find an element that satisfies a given predicate. There are a couple of functions that can be used for this, depending on your specific needs:

• find() searches through the array and returns the value of the first element that satisfies a given condition, or undefined if no such element is found
• findIndex() performs a similar task, but instead of returning an element, it returns the index of the first element in the array that satisfies the condition, or -1 if none were found

The similarity to includes() and indexOf() is clear; these functions search for a specific value instead of an element that satisfies a more general condition. We can easily ...