There are various way to reverse the string in javascript. Let try few ways to achieve same.

1. Using inbuilt methods

let str = 'singhak';
let strArray = str.split('');
let reverseStr = strArray.reverse().join('');

console.log(reverseStr) //kahgnis

2. Using recursion

function reverse(str) {
    // Base condition
    if (str.length === 1)
        return str
    else
        return str.charAt(str.length - 1) + reverse(str.substr(0, str.length - 1));
}
console.log(reverse('singhak')) //kahgnis

3. Using swap method

function reverse(inputstr) {
    let i, j;
    let str = inputstr.split('');
    for (j = str.length - 1, i = 0; j > i; i++, j--) {
        let temp = str[i]
        console.log(temp)
        str[i] = str[j];
        str[j] = temp;
    }
    return str.join('');
}

console.log(reverse('singhak')) //kahgnis