code: function arraySpliceOut(mutate, at, arr) {
      var newLen = arr.length - 1;
      var i = 0;
      var g = 0;
      var out = arr;
      if (mutate) {
          i = g = at;
      } else {
          out = new Array(newLen);
          while (i < at) {
              out[g++] = arr[i++];
          }
      }
      ++i;
      while (i <= newLen) {
          out[g++] = arr[i++];
      }if (mutate) {
          out.length = newLen;
      }
      return out;
  }
docs: Remove a value from an array.
  
  @param mutate Should the input array be mutated?
  @param at Index to remove.
  @param arr Array.