var-let-bench.js

const iterations = 100000000;

(() => {
  console.time('Var While');
  var iVarWhile = 0;
  while (iVarWhile < iterations) {
    iVarWhile += 2;
  }
  console.timeEnd('Var While');
})();

(() => {
  console.time('Let While');
  let iLetWhile = 0;
  while (iLetWhile < iterations) {
    iLetWhile += 2;
  }
  console.timeEnd('Let While');
})();

(() => {
  console.time('Var For');
  var iVarFor = 0;
  for (iVarFor = 0; iVarFor < iterations; iVarFor += 2) {}
  console.timeEnd('Var For');
})();

(() => {
  console.time('Let For');
  let iLetFor = 0;
  for (iLetFor = 0; iLetFor < iterations; iLetFor += 2) {}
  console.timeEnd('Let For');
})();