function sumOfNumbers(input) {
    let digitAsText = "" + input[0];
 
    let sum = 0;
    for (let index = 0; index < digitAsText.length; index++) {
        let n = Number(digitAsText.charAt(index));
        sum += n;  
    }
 
console.log(`The sum of the digits is:${sum}`);
 
}
sumOfNumbers(["1234"])