How can I create every combination possible for the contents of two arrays?

Question

I have two arrays:

var array1=[\"A\",\"B\",\"C\"];

var array2=[\"1\",\"2\",\"3\"];

How can I set another array to contain every combinatio

Answer 1

Seeing a lot of for loops in all of the answers...

Here's a recursive solution I came up with that will find all combinations of N number of arrays by taking 1 element from each array:

const array1=["A","B","C"]
const array2=["1","2","3"]
const array3=["red","blue","green"]

const combine = ([head, ...[headTail, ...tailTail]]) => {
  if (!headTail) return head

  const combined = headTail.reduce((acc, x) => {
    return acc.concat(head.map(h => `${h}${x}`))
  }, [])

  return combine([combined, ...tailTail])
}

console.log('With your example arrays:', combine([array1, array2]))
console.log('With N arrays:', combine([array1, array2, array3]))