JSFiddle - React, Tailwind, and code Playground

by Lazaro Contreras

JavaScript

function findEvenIndex(arr)
{
  var r = -1;
  arr.forEach(function(e, i){
  r = (i< arr.length - 1 && i > 0) ? (arr.slice(0,i).reduce((a,b) => a + b) === arr.slice(i + 1).reduce((a,b) => a + b)) ? (i > r) ? i : r : r : r;
  });
  return r;
}
console.log(findEvenIndex([20,10,30,10,10,15,35]),3, "The array was: [20,10,30,10,10,15,35] \n");