Javascript Combination Generator based on N number of objects

Question

I need to make a function that receives an array and generates all combinations based on N param size. Example:

function comb([1,2],3)
out: 
[[1,1,1],
[1,1,2],
[1,2,1],
[1,2,2],
[2,1,1],
[2,1,2],
[2,2,1],
[2,2,2]]

or:

function comb([4,1],2)
out:
[[4,4],
[4,1],
[1,4],
[1,1]]

Show an attempt at solving it and then ask if you are stuck (and show your code). — Ivan86, Apr 13 '20 at 21:06
This is basically not the [cartesian product](https://stackoverflow.com/q/15298912/1048572), but more like the "cartesian power" - the array multiplied with itself n times. — Bergi, Apr 13 '20 at 21:09
You can use the "Odometer" method: https://stackoverflow.com/a/52598239/6438819 — RaffleBuffle, Apr 13 '20 at 22:28

score 0 · Answer 1 · answered Apr 14 '20 at 14:13

I found a solution from Nina Scholz
JavaScript - Generating combinations from n arrays with m elements

and i made an adaptation, this is the result:

var result = 0;
function combination(parts,N){
    var parts_normalize = []
  while (N--) parts_normalize.push(parts)
    result = parts_normalize.reduce((a, b) => a.reduce((r, v) => r.concat(b.map(w => [].concat(v, w))), []));
  console.log(result)
}

this is working well but, someone can explain what is happening in this function xD i am totaly lost

Javascript Combination Generator based on N number of objects

1 Answers1