Javascript - keep only first & last value in Array

Question

What is the best way to get only the first and last value in Array?

If arr = [0,1,2,3]

Result: arr = [0,3]

If arr = [0]

Result: arr = [0]

If arr = []

Expect result: arr = []

I could get in this way.

[arr[0], arr[arr.length - 1]]

But I want to know if there is a better way to get.

`arr.reduce((acc,curr,i)=>i===0||i===arr.length-1?[...acc,curr]:acc,[])` — Will Jenkins, Mar 06 '20 at 15:52
@WillJenkins there's an open spot in the next Obfuscated Coding competition for you ;-) — jarmod, Mar 06 '20 at 19:53

score 2 · Answer 1 · answered Mar 06 '20 at 15:38

function firstLast(arr) {
    if (arr.length < 2) return arr;
    return [arr[0], arr[arr.length - 1]];
}

Error check for the case where the length of the array is less than 2, if so, just return the array.

If the array is long enough to get start and end, just return a new array with that start and end.

1 Answers1