angular/angular.js

<div ng-app="eventDelegationBenchmark">
<div ng-controller="DataController as ctrl">
<div class="container-fluid">

<p>
Impact of event delegation.
</p>

<p>
<label>
  Number of ngRepeats:
  <input type="number" ng-model="ctrl.ngRepeatCount">
</label>
</p>

<p>
<div class="radio"><label><input type=radio ng-model="benchmarkType" value="ngClick">ngClick</label></div>
<div class="radio"><label><input type=radio ng-model="benchmarkType" value="ngClickNoJqLite">ngClick without jqLite</label></div>
<div class="radio"><label><input type=radio ng-model="benchmarkType" value="ngShow">baseline: ng-show</label></div>
<div class="radio"><label><input type=radio ng-model="benchmarkType" value="textInterpolation">baseline: text interpolation</label></div>
<div class="radio"><label><input type=radio ng-model="benchmarkType" value="dlgtClick">delegate event directive (only compile)</label></div>
<div class="radio"><label><input type=radio ng-model="benchmarkType" value="noopDir">baseline: noop directive (compile and link)</label></div>
<div class="radio"><label><input type=radio ng-model="benchmarkType" value="noop">baseline: no directive</label></div>
</p>

<p>
How to read the results:
<ul>
  <li>The benchmark measures how long it takes to instantiate a given number of directives</li>
  <li>ngClick is compared against ngShow and text interpolation as baseline. The results show
      how expensive ngClick is compared to other very simple directives that touch the DOM.
  </li>
  <li>To measure the impact of jqLite.on vs element.addEventListener there is also a benchmark
      that as a modified version of ngClick that uses element.addEventListener.
  </li>
  <li>The delegate event directive is compared against a noop directive with a compile and link function and the case with no directives.
      The result shows how expensive it is to add a link function to a directive, as the delegate event directive has none.
  </li>
</ul>
</p>

<p>
Results as of 7/31/2014:
<ul>
  <li>ngClick is very close to ngShow and text interpolation, especially when looking at a version of ngClick that does not use jqLite.on but element.addEventListener instead.</li>
  <li>A delegate event directive that has no link function has the same speed as a directive with link function. I.e. ngClick is slower compared to the delegate event directive only because ngClick touches
  the DOM for every element</li>
  <li>A delegate event directive could be about 50% faster than ngClick. However, the overall performance
      benefit depends on how many (and which) other directives are used on the same element
      and what other things are part of the measures use case.
      E.g. rows of a table with ngRepeat that use ngClick will probably also contain text interpolation.
  </li>
</ul>
</p>

Debug output:
<ng-switch on="benchmarkType">
  <div ng-switch-when="ngClick">
    <div>
      <span ng-repeat="row in ctrl.rows">
        <span ng-click="a()">1</span>
        <span ng-click="a()">1</span>
        <span ng-click="a()">1</span>
        <span ng-click="a()">1</span>
      </span>
    </div>
  </div>
  <div ng-switch-when="ngClickNoJqLite">
    <div>
      <span ng-repeat="row in ctrl.rows">
        <span native-click="a()">1</span>
        <span native-click="a()">1</span>
        <span native-click="a()">1</span>
        <span native-click="a()">1</span>
        <span native-click="a()">1</span>
      </span>
    </div>
  </div>
  <div ng-switch-when="ngShow">
    <div>
      <span ng-repeat="row in ctrl.rows">
        <span ng-show="true">1</span>
        <span ng-show="true">1</span>
        <span ng-show="true">1</span>
        <span ng-show="true">1</span>
        <span ng-show="true">1</span>
      </span>
    </div>
  </div>
  <div ng-switch-when="textInterpolation">
    <div>
      <span ng-repeat="row in ctrl.rows">
        <span>{{row}}</span>
        <span>{{row}}</span>
        <span>{{row}}</span>
        <span>{{row}}</span>
        <span>{{row}}</span>
      </span>
    </div>
  </div>
  <div ng-switch-when="dlgtClick">
    <div>
      <span ng-repeat="row in ctrl.rows">
        <span dlgt-click="a()">1</span>
        <span dlgt-click="a()">1</span>
        <span dlgt-click="a()">1</span>
        <span dlgt-click="a()">1</span>
        <span dlgt-click="a()">1</span>
      </span>
    </div>
  </div>
  <div ng-switch-when="noopDir">
    <div>
      <span ng-repeat="row in ctrl.rows">
        <span noop-dir>1</span>
        <span noop-dir>1</span>
        <span noop-dir>1</span>
        <span noop-dir>1</span>
        <span noop-dir>1</span>
      </span>
    </div>
  </div>
  <div ng-switch-when="noop">
    <div>
      <span ng-repeat="row in ctrl.rows">
        <span>1</span>
        <span>1</span>
        <span>1</span>
        <span>1</span>
        <span>1</span>
      </span>
    </div>
  </div>

</ng-switch>

</div>
</div>
</div>