object-entries-values-slow-path-bench.js

if (typeof console === 'undefined') console = {log:print};

function forIn(o) {
  let result = 0;
  for (const key in o) {
    if (Object.prototype.hasOwnProperty.call(o, key)) {
      result += key.length + o[key].length;
    }
  }
  return result;
}

function objectKeys(o) {
  let result = 0;
  for (const key of Object.keys(o)) {
    result += key.length + o[key].length;
  }
  return result;
}

function objectKeysAndValues(o) {
  let result = 0;
  const keys = Object.keys(o);
  const values = Object.values(o);
  for (let i = 0; i < keys.length; ++i) {
    result += keys[i].length + values[i].length;
  }
  return result;
}

function objectEntries(o) {
  let result = 0;
  for (const [key, val] of Object.entries(o)) {
    result += key.length + val.length;
  }
  return result;
}

var TESTS = [
  forIn,
  objectKeys,
  objectKeysAndValues,
  objectEntries
];
var n = 1e6;
var OBJECTS = [
  {},
  {a:'', b:'', c:'', d:''},
  {1:'', 2:'', 3:'', 4:'', 5:'', f:'', g:''},
  {[Symbol('test')]: '', a: ''},
  {a:'', b:'', c:'', d:'', e:'', f:'', g:'', h:'', i:'', j:'', k:'', l:''}
];
Object.defineProperties(OBJECTS[3], {
  'b': {
    enumerable: false,
    value: ''
  },
  1: {
    enumerable: true,
    value: ''
  }
});

function test(fn) {
  for (var i = 0; i < n; ++i) {
    let result = 0;
    for (const o of OBJECTS) {
      result += fn(o);
    }
    if (result !== 25) throw new Error(`Invalid result ${result}`);
  }
}

for (var j = 0; j < TESTS.length; ++j) {
  test(TESTS[j]);
}

for (var j = 0; j < TESTS.length; ++j) {
  var startTime = Date.now();
  test(TESTS[j]);
  console.log(TESTS[j].name + ':', (Date.now() - startTime), 'ms.');
}