Display Table of Food Orders in a Restaurant LeetCode solution in JavaScript

1
var displayTable = function (orders) {
2
  var mapOrders = {};
3
  var tables = [];
4
  var dishes = [];
5
  for (var i = 0; i < orders.length; i++) {
6
    //if entry of table doesn't exist in mapOrders
7
    if (mapOrders[orders[i][1]] == undefined) {
8
      //conver table number to integer
9
      var tableNo = Number(orders[i][1]);
10
      mapOrders[tableNo] = {};
11
      mapOrders[tableNo][orders[i][2]] = 1;
12
      //if table number doesn't exist in table array, push it in the table array
13
      if (!tables.includes(tableNo)) {
14
        tables.push(tableNo);
15
      }
16
      //if dish doesn't exist in dishes array, push it in the dishes array
17
      if (!dishes.includes(orders[i][2])) {
18
        dishes.push(orders[i][2]);
19
      }
20
    } else {
21
      //if entry of table exists in mapOrders
22
      //conver table number to integer
23
      var tableNo = Number(orders[i][1]);
24
      var entry = mapOrders[tableNo];
25
      //check if entry of dish exists in for that table in mapOrders
26
      if (entry[orders[i][2]] == undefined) {
27
        entry[orders[i][2]] = 1;
28
      } else {
29
        entry[orders[i][2]] = entry[orders[i][2]] + 1;
30
      }
31
      //if dish doesn't exist in dishes array, push it in the dishes array
32
      if (!dishes.includes(orders[i][2])) {
33
        dishes.push(orders[i][2]);
34
      }
35
    }
36
  }
37
  //sort tables and dishes
38
  tables.sort(function (a, b) {
39
    return a - b;
40
  });
41
  dishes.sort();
42
  //append word "Table" with all dish names om row[0] of result
43
  var res = [["Table"]];
44
  for (var i = 0; i < dishes.length; i++) {
45
    res[0].push(dishes[i]);
46
  }
47
  // read through map based on sorted table order
48
  for (var i = 0; i < tables.length; i++) {
49
    // append result in a temp array
50
    var tmp = [];
51
    //converting number to string using ""+
52
    tmp.push("" + tables[i]);
53
    for (var j = 0; j < dishes.length; j++) {
54
      if (mapOrders[tables[i]][dishes[j]] == undefined) {
55
        //if dish doesn't exist against that table then append "0" to the result for that dish
56
        tmp.push("" + 0);
57
      } else {
58
        //if dish exists against that table then append value in mapOrders for that pair of (table,dish) to the result
59
        tmp.push("" + mapOrders[tables[i]][dishes[j]]);
60
      }
61
    }
62
    //append the temp array in result
63
    res.push(tmp);
64
  }
65
  return res;
66
};