Find all Permutations in JavaScript

1const findPermutation = (num) => {
2  const results = []
3  const num_data = num.split('')
4  function permute(arr, mem) {
5    let cur
6    const tmp = mem || []
7
8    for (var i = 0; i < arr.length; i++) {
9      cur = arr.splice(i, 1)
10      if (arr.length === 0) {
11        results.push(tmp.concat(cur))
12      }
13      permute(arr.slice(), tmp.concat(cur))
14      arr.splice(i, 0, cur[0])
15    }
16
17    return results
18  }
19  return permute(num_data)
20    .map((t) => t.join(''))
21    .filter((value, index, self) => self.indexOf(value) === index)
22}
23

1findPermutation('123');
2[ '123', '132', '213', '231', '312', '321' ]
3
4findPermutation('abcd');
5[
6  'abcd', 'abdc', 'acbd',
7  'acdb', 'adbc', 'adcb',
8  'bacd', 'badc', 'bcad',
9  'bcda', 'bdac', 'bdca',
10  'cabd', 'cadb', 'cbad',
11  'cbda', 'cdab', 'cdba',
12  'dabc', 'dacb', 'dbac',
13  'dbca', 'dcab', 'dcba'
14]
15
16findPermutation('aabc');
17[
18  'aabc', 'aacb',
19  'abac', 'abca',
20  'acab', 'acba',
21  'baac', 'baca',
22  'bcaa', 'caab',
23  'caba', 'cbaa'
24]
25