Newton method for square root calculation in JavaScript. This code can be improved.

newtonRoot.js

const newtonSquareRoot = (num) => {
    let x = 1;
    let result;
    
    for (let i = 0; i < 20; i++)
    {
        result = x - ( x*x - num )/( 2*x );
        x = result;
    }

    return result;
}

let number = 123;
console.log(newtonSquareRoot(number));