JavaScript looping arrays

The example shows four ways of looping over a JavaScript array.

JavaScript looping arrays

const words = ["pen", "pencil", "rock", "sky", "earth"];

words.forEach(e => console.log(e));

for (let word of words) {
    
    console.log(word);
}

for (let idx in words) {
    
    console.log(words[idx]);
}

const len = words.length;

for (let i = 0; i < len; i++) {

    console.log(words[i]);
}

const i = 0;

while (i < len) {
    
    console.log(words[i]);
    i++;
}

We use the forEach() method to traverse the array. It executes the provided function once for each array element:

words.forEach(e => console.log(e));

With for of loop, we go over the values of the array:

for (let word of words) {
    
    console.log(word);
}

With for in loop, we go over the indexes of the array:

for (let idx in words) {
    
    console.log(words[idx]);
}

Here we use the C-like for loop to traverse the array:

var len = words.length;

for (let i = 0; i < len; i++) {

    console.log(words[i]);
}

var i = 0;

while (i < len) {
    
    console.log(words[i]);
    i++;
}