const allAnagrams = (string) => {
  var arr = string.split('');
//   let arr = Array.from(string);
  let results = [];
  for (let permutation of permute(arr)) {
    results.push(permutation.join(''));
  }
  return results;
};

const permute = function* (permutation) {
  const length = permutation.length;
  let c = Array(length).fill(0);
  let i = 1;

  yield permutation;
  // iterate through
  while (i < length) {
    if (c[i] < i) {
      var k = (i % 2) ? c[i] : 0;
      var p = permutation[i];
      permutation[i] = permutation[k];
      permutation[k] = p;
      c[i]++;
      i = 1;
      yield permutation;
    } else {
      c[i] = 0;
      i++;
    }
  }
};

const test = allAnagrams('test');
console.log(test);