loop_reduce_test.ts

// run using: node --expose_gc loop_reduce_test.ts   
// to allow for high precision timing

function arrayReduceTest(ary) {

  return ary.reduce((acc, x) => {
      return acc + x;
    }, 0);  
}

function arrayLoopTest(ary) {

  var acc = 0, i;

  for (i = 0; i < ary.length; i++) {
    acc += ary[i];
  }

  return acc;

}

function runTest(length) {

  var ary;
  
  var tests = [
    arrayReduceTest,
    arrayLoopTest, 
  ];

  tests.map(function(fn){
    ary = arrayCreate(length);
    precisionTime(fn.name, function(){
       fn(ary);
    });
  });  
}

runTest(1000000);




/* util functions */

function arrayCreate(length) {
   return Array(length).fill(1);
}


function precisionTime(testName, fn) {
  global.gc();
  var iStart = process.hrtime();
  fn();
  console.log(padEnd(testName, 20), padEnd(process.hrtime(iStart), 20), padEnd(process.memoryUsage().heapUsed.toLocaleString(), 20));
}

function padEnd(str, length) {
  if (str.length >= length) {
    return str;
  } else {
    return str + " ".repeat(length - str.length);
  }
}