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'use strict'
const permutate = (aString) => {
if (typeof aString !== 'string' || !aString) {
throw new Error('The arg must be a valid, non empty string')
}
const characters = aString.split('')
let permutations = [[characters.shift()]]
while (characters.length) {
const currentCharacter = characters.shift()
permutations = calculateCurrentCharacterPermutation(
permutations,
currentCharacter
)
}
return permutations
.map((character) => character.join(''))
.filter((item, index, self) => self.indexOf(item) === index)
.sort()
}
const calculateCurrentCharacterPermutation = (
allPermutations,
currentCharacter
) => {
const currentPermutations = []
allPermutations.forEach((permutation) => {
let index = 0
while (index