Recursive nested addition

function addElementsOfNestedArr(arr){
    let sum=0
    for(let x of arr){
        if(typeof x==="number"){
            console.log("adding ",x)
            sum+=x;
        }
        else{
            console.log(x,sum)
            
            let val=addElementsOfNestedArr(x);
        sum+=val;
        console.log("adding return",val)
            
        }
    }
    return sum
}

const nestedArray=[1, 2, 3, 4, 5, [6, 7, 8], 9, [[10, 11], 13, [14]]];


console.log(addElementsOfNestedArr(nestedArray))