The n times dribbling strings in JavaScript

We are required to write a JavaScript function that takes in a string and a number, say n, and the function should return a new string in which all the letters of the original string are repeated n times.

For example: If the string is ?

const str = 'how are you'

And the number n is 2.

Output

Then the output should be ?

const output = 'hhooww aarree yyoouu'

Therefore, let's write the code for this function ?

Using String.prototype.repeat()

The most straightforward approach is to iterate through each character and use the built-in repeat() method:

const str = 'how are you';
const repeatNTimes = (str, n) => {
    let res = '';
    for(let i = 0; i < str.length; i++){
        // using the String.prototype.repeat() function
        res += str[i].repeat(n);
    };
    return res;
};
console.log(repeatNTimes(str, 2));

hhooww aarree yyoouu

Using Array Methods

Alternatively, we can use array methods for a more functional approach:

const str = 'how are you';
const repeatNTimes = (str, n) => {
    return str.split('').map(char => char.repeat(n)).join('');
};
console.log(repeatNTimes(str, 3));
console.log(repeatNTimes('hello', 2));

hhhooowww aaaarrreee yyyooouuu
hheelllloo

Using Manual Loop

For educational purposes, here's how to implement it without using the repeat() method:

const str = 'test';
const repeatNTimes = (str, n) => {
    let result = '';
    for(let i = 0; i < str.length; i++){
        for(let j = 0; j < n; j++){
            result += str[i];
        }
    }
    return result;
};
console.log(repeatNTimes(str, 4));

tttteeeesssstttt

Comparison

Conclusion

The String.prototype.repeat() method provides the cleanest and most efficient solution for repeating characters in a string. Choose the array method approach when working in a functional programming style.