392 B
392 B
title, tags
| title | tags |
|---|---|
| head | array,beginner |
Returns the head of a list.
Check if arr is truthy and has a length property, use arr[0] if possible
to return the first element, otherwise return undefined
const head = arr => (arr && arr.length ? arr[0] : undefined);
head([1, 2, 3]); // 1
head([]); // undefined
head(null); // undefined
head(undefined); // undefined