Counting Sort Visualization using JavaScript

var container = document.getElementById("array");

// Function to generate the array of blocks
function generatearray() {
  for (var i = 0; i < 20; i++) {
    // Return a value from 1 to 100 (both inclusive)
    var value = Math.ceil(Math.random() * 20);

    // Creating element div
    var array_ele = document.createElement("div");

    // Adding class 'block' to div
    array_ele.classList.add("block");

    // Adding style to div
    array_ele.style.height = `${value * 13}px`;
    array_ele.style.transform = `translate(${i * 30}px)`;

    // Creating label element for displaying
    // size of particular block
    var array_ele_label = document.createElement("label");
    array_ele_label.classList.add("block_id");
    array_ele_label.innerText = value;

    // Appending created elements to index.html
    array_ele.appendChild(array_ele_label);
    container.appendChild(array_ele);
  }
}

// Function to generate the frequency array
var count_container = document.getElementById("count");
function generate_freq() {
  for (var i = 0; i < 20; i++) {
    // Creating element div
    var array_ele2 = document.createElement("div");

    // Adding class 'block2' to div
    array_ele2.classList.add("block2");

    // Adding style to div
    array_ele2.style.height = `${20}px`;
    array_ele2.style.transform = `translate(${i * 30}px)`;

    // index of freq array
    var array_ele_idx = document.createElement("label");
    array_ele_idx.classList.add("block_id2");
    array_ele_idx.innerText = i + 1;

    //giving initial freq to all blocks as 0
    var array_ele_label2 = document.createElement("label");
    array_ele_label2.classList.add("block_id3");
    array_ele_label2.innerText = 0;

    // Appending created elements to index.html
    array_ele2.appendChild(array_ele_label2);
    array_ele2.appendChild(array_ele_idx);
    count_container.appendChild(array_ele2);
  }
}

// Asynchronous CountingSort function
async function CountingSort(delay = 250) {
  var blocks = document.querySelectorAll(".block");

  // To store frequency of every block
  for (var i = 0; i < blocks.length; i += 1) {
    //To highlight the current traversed block
    blocks[i].style.backgroundColor = "#FF4949";

    //Extracting the value of current block
    var value = Number(blocks[i].childNodes[0].innerHTML);

    var freq_array = document.getElementsByClassName("block_id3");

    freq_array[value - 1].innerText++;

    // To wait for .1 sec
    await new Promise((resolve) =>
      setTimeout(() => {
        resolve();
      }, delay)
    );

    //Changing to previous color
    blocks[i].style.backgroundColor = "#6b5b95";
  }

  //Sorting by using frequency array
  var idx = 0;
  for (var i = 0; i < blocks.length; i += 1) {
    var freq = document.getElementsByClassName("block_id3");

    var temp = Number(freq[i].innerText);

    var freq_block = document.getElementsByClassName("block2");

    //changing color of freq block
    freq_block[i].style.backgroundColor = "#FF4949";

    // To wait for .1 sec
    await new Promise((resolve) =>
      setTimeout(() => {
        resolve();
      }, 2 * delay)
    );

    if (temp == 0) {
      //changing color of freq block to previous one
      freq_block[i].style.backgroundColor = "darkgray";
      continue;
    }

    var block_label = document.getElementsByClassName("block_id");

    //sorting the block array
    for (var j = 0; j < temp; j++) {
      blocks[idx].style.height = `${(i + 1) * 13}px`;
      block_label[idx].innerText = i + 1;
      idx++;
    }

    //changing color of freq block to previous one
    freq_block[i].style.backgroundColor = "darkgray";

    // To wait for .1 sec
    await new Promise((resolve) =>
      setTimeout(() => {
        resolve();
      }, 2 * delay)
    );
  }
}

// Calling generatearray function
generatearray();

// Calling generate_freq function
generate_freq();

// Calling CountingSort function
CountingSort();