JavaScript Array Series – Custom toString() Methods

In my previous blog, I explained how the Array length property works and also created my own version of it without using the built-in length property.Today, I continued the same learning journey by creating my own versions of JavaScript array methods:

toString()

Instead of directly using JavaScript's built-in methods, I tried to understand the internal working of these methods by implementing them manually.

Creating My Own toString() Method

The toString() method converts an array into a string.

Example:

const arr = [1, 2, 3];

console.log(arr.toString()); // "1,2,3"

In this program, I manually converted the array into a string.

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My Approach

arr = [1, 2, 3, 4, 5];
str = "";

len = countOfLength();

for (let count of arr) {
    if (count < len) {
        str = str + count + ",";
    } else {
        str = str + count;
    }
}

function countOfLength() {
    let lengthDemo = 0;

    for (let count of arr) {
        lengthDemo++;
    }

    return lengthDemo;
}

console.log(str);

How It Works

Step 1: Count the array length
len = countOfLength();

I first calculated the array length manually using a custom function.

function countOfLength() {
    let lengthDemo = 0;

    for (let count of arr) {
        lengthDemo++;
    }

    return lengthDemo;
}

This function loops through the array and counts the total number of elements.

Step 2: Loop through the array
for (let count of arr)

This loop visits every element one by one.

Step 3: Build the string
str = str + count + ",";

Each value is added to the string along with a comma.

For the last element, I avoided adding an extra comma.

Finally, the output becomes:

"1,2,3,4,5"

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Building methods manually is a great way to understand how JavaScript works internally. Instead of only using built-in methods, implementing them ourselves helps improve problem-solving skills and strengthens JavaScript fundamentals.

I will continue this series by implementing more JavaScript array methods manually and share my learning journey step by step in upcoming blogs.

Stay tuned for the next part! 👋