depthSum

by Paco86

JavaScript

function depthSum(array, depth=1){
	let sum = 0;
  for(let i=0; i<array.length; i++){
  	if(Array.isArray(array[i])){
    	sum += depthSum(array[i], depth+1)
    }else{
    	sum += array[i]*depth;
    }
  }
  return sum;
}

let arr = [1, 2, [3], 4]
console.log(depthSum(arr));