Merge two arrays with alternating Values

Question

i would like to merge 2 arrays with a different length:

let array2 = [\"a\", \"b\", \"c\", \"d\"];
let array2 = [1, 2];

let outcome = [\"a\",1 ,\"b\", 2, \"         


        

Answer 1

You could iterate the min length of both array and build alternate elements and at the end push the rest.

var array1 = ["a", "b", "c", "d"],
    array2 = [1, 2],
    result = [],
    i, l = Math.min(array1.length, array2.length);
    
for (i = 0; i < l; i++) {
    result.push(array1[i], array2[i]);
}
result.push(...array1.slice(l), ...array2.slice(l));

console.log(result);

Solution for an arbitrary count of arrays with a transposing algorithm and later flattening.

var array1 = ["a", "b", "c", "d"],
    array2 = [1, 2],
    result = [array1, array2]
        .reduce((r, a) => (a.forEach((a, i) => (r[i] = r[i] || []).push(a)), r), [])
        .reduce((a, b) => a.concat(b));
    
console.log(result);