CreatePermutations.js

/*
a permutation of a set is, loosely speaking, an arrangement of its members into a sequence or linear order, or if the set is already ordered, a rearrangement of its elements.
The word "permutation" also refers to the act or process of changing the linear order of an ordered set
More at : https://en.wikipedia.org/wiki/Permutation
*/

const createPermutations = (str) => {
 // convert string to array
 const arr = str.split('')

 // get array length
 const strLen = arr.length
 // this will hold all the permutations
 const perms = []
 let rest
 let picked
 let restPerms
 let next

 // if strLen is zero, return the same string
 if (strLen === 0) {
 return [str]
 }
 // loop to the length to get all permutations
 for (let i = 0; i < strLen; i++) {
 rest = Object.create(arr)
 picked = rest.splice(i, 1)

 restPerms = createPermutations(rest.join(''))

 for (let j = 0, jLen = restPerms.length; j < jLen; j++) {
 next = picked.concat(restPerms[j])
 perms.push(next.join(''))
 }
 }
 return perms
}
export { createPermutations }