Write a function that takes an array of numbers and returns the sum of each number multiplied by its position in the array.

multiply-array.js

// The final total as a global variable
var total = 0;

// This function will take an element and its index as param.
// We are just declaring the function here
function logArrayElements(element, index) {
  // multipliying the index and element value
  value = index * element;
  
  // This console.log is just to see exactly what's happening in the console
  console.log("index: "+index + " * value: " + element + " = " + value);
  
  // After each call of the function, I'm adding the current value to the grand total
  total += value; 
}

// Calling the function !
[1, 2, 3, 4].forEach(logArrayElements);

// And grand total is...
console.log("Grand total : " + total);