Run results for: Underscore 1.6 vss Underscore 1.9

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36

Browser: Chrome 76

Operating system: Windows

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
Underscore 1.6	167.9 Ops/sec
Underscore 1.9	162.1 Ops/sec

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.6.0/underscore-min.js'></script>
<script type="text/javascript">
  window.u1 = _;
  _ = null;
</script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.9.1/underscore-min.js'></script>
<script type="text/javascript">
  window.u2 = _;
  _ = null;
</script>

Script Preparation code:

  var data = u1.range(10000).map(function(i) {
    return {
      counter: i
    }
  });
  
  function isOdd(num) {
    return num % 2 === 1;
  }
  
  function square(num) {
    return num * num;
  }
  
  function lessThanThreeDigits(num) {
    return num.toString().length < 3;
  }

Tests:

Underscore 1.6
var result = u1.chain(data) .map(item => item.counter) .filter(isOdd) .map(square) .filter(lessThanThreeDigits) .value();
Underscore 1.9
var result = u2.chain(data) .map(item => item.counter) .filter(isOdd) .map(square) .filter(lessThanThreeDigits) .value();