interweave two arrays. Can be different sizes.

interweave.js

export default function interleave(arr1, arr2){
    "use strict";
    let combined = []
    let arr1_len = arr1.length
    let arr2_len = arr2.length
    while(arr1_len>0 || arr2_len >0){
        if(arr1_len>0){
            combined.push(arr1.shift())
            arr1_len--
        }
        if(arr2_len>0){
            combined.push(arr2.shift())
            arr2_len--
        }
    }
    return combined
}
     console.log(interleave([1,1,1,1],[2])) // [1, 2, 1, 1, 1]