Find the frequency counter of values in the array using JavaScript Program

Here we have one example find the frequency of the similar numbers that occur in the array list.

const example = [1, 4, 5, 3, 3, 2, 4, 5, 5, 8, 10];

const obj = {};

for (let index = 0; index < example.length; index++) {
    const element = example[index];
    obj[element] = (obj[element] || 0) + 1;
}

console.log("The Frequency of the numbers in array is: \n");
console.log(obj);

Output of the program is :

The Frequency of the numbers in array is:

{ '1': 1, '2': 1, '3': 2, '4': 2, '5': 3, '8': 1, '10': 1 }

Here's a breakdown of what the code does:

1. Create an array called `example` with some numbers.

const example = [1, 4, 5, 3, 3, 2, 4, 5, 5, 8, 10];

2. Create an empty object called `obj` to store the counts of each element.

 const obj = {};

3. Iterate over each element in the `example` array using a `for` loop.

 for (let index = 0; index < example.length; index++) {
     const element = example[index];
     // ...
   }

4. Inside the loop, access the current element and use it as a key in the `obj` object.

 obj[element] = (obj[element] || 0) + 1;

   - If the current element (`element`) is not yet a key in the `obj` object, `obj[element]` will be `undefined`, so `(obj[element] || 0)` will be evaluated as `0`.
   - Then, `0 + 1` will be assigned to `obj[element]`, effectively initializing the count for that element as `1`.

   - If the current element (`element`) is already a key in the `obj` object, `(obj[element] || 0)` will retrieve its current count.
   - Then, the count is incremented by `1` by adding `1` to the current value.

5. After the loop finishes, the `obj` object will contain the counts of each element in the `example` array.

For example, using the `example` array from above, the resulting `obj` object would be:

{
  1: 1,
  4: 2,
  5: 3,
  3: 2,
  2: 1,
  8: 1,
  10: 1
}

This code is a basic implementation of counting element occurrences using an object as a counter. It can be useful in various scenarios where you need to analyze the frequency or distribution of elements in an array.