A code snippet to produce permutation of an array

README.md

Array Combinator

A library for producing all possible combinations of an array. All with the question of how many ways can elements of an array be arranged. If computationally too complex will return null.

This draws back to the idea of Permutation and Combination. E.g [AB, BA]. Here, we have 1 combination and 2 permutation. Since permutation is concerned with the arrangement, where order does matter. While in combination they are considered same since order doesn't matter.

Formula for combination:

c = n!       

;where
;n = number of elements
;c = number of combinations

ArrayCombination.js

const test_array = [1, 2, 3];

function get_combinations(arr) {
  var permArr = [],
    usedChars = [];
  function permute(input) {
    var i, ch;
    for (i = 0; i < input.length; i++) {
      ch = input.splice(i, 1)[0];
      usedChars.push(ch);
      if (input.length == 0) {
        permArr.push(usedChars.slice());
      }
      permute(input);
      input.splice(i, 0, ch);
      usedChars.pop();
    }
    return permArr;
  }
  return permute(arr);
}

const names = "spiff jekey green";

console.log((get_combinations(names.split(" "))));