Angular-Typescript: Why does my shell sort stops after 3 loops throughout the whole array

Question

I am creating a sorting visualizer and I already got some algorithms done: bubble, selection, insertion. I am trying to implement shell sort as well, but the sorting stops after 3 iterations through the entire array. Until that happens, the sorting process seems fine. Why does this happen? I can see it stopping because I update the chart after each iteration of the inner loop. Here is my code:

async ShellSort(delay = 5) { 
    for (let gap = Math.floor(this.data.length / 2); gap > 0; gap /= 2) {
      for (let i = gap; i < this.data.length; i++) {
        let temp = this.data[i];
        let j = i;
        while (j > gap && temp < this.data[j - gap]) {
          this.data[j] = this.data[j - gap];
          j -= gap;
        }
        this.data[j] = temp;

        //update the chart
        await new Promise(resolve =>
          setTimeout(() => {
            resolve();
          }, delay)
        );
        this.draw();

      }

    }
  }

Answer 1

Oh, never mind, the algorithm works fine, its just that since JavaScript has only the number type and not int, I have to explicitly do math.floor for each gap to get a whole number otherwise I would be accessing a floating point index which is not possible.