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

A bit verbose solution that lets you choose which array goes first

const a = ['a', 'b', 'c'];
const b = [1, 4];
const combineAlternatingArrays = (a, b) => {
  let combined = [];
  const [shorter, larger] = [a, b].sort((a, b) => a.length -b.length);

  shorter.forEach((item, i) => {
    combined.push(larger[i], item);
  })
  combined.push(...larger.slice(shorter.length));

  return combined;
}
console.log(combineAlternatingArrays(a, b));

It is also possible to use a reduce, but the syntax is less clear in my opinnion.

const a = ['a', 'b', 'c'];
const b = [1, 4];
const combineAlternatingArrays = (a, b) => {
  const [shorter, larger] = [a, b].sort((a, b) => a.length -b.length);

  return shorter.reduce(
    (combined, next, i, shorter) => {
      return (i === (shorter.length -1)) ? [...combined, larger[i], next, ...larger.slice(shorter.length)] : [...combined, larger[i], next];
    },
    []
  );
}
console.log(combineAlternatingArrays(a, b));