1  // Public: Measure how long a function takes to run.
 2  //
 3  // description - A {String} description that will be logged to the console when
 4  //               the function completes.
 5  // fn - A {Function} to measure the duration of.
 6  //
 7  // Returns the value returned by the given function.
 8  window.measure = function(description, fn) {
 9    let start = Date.now();
10    let value = fn();
11    let result = Date.now() - start;
12    console.log(description, result);
13    return value;
14  };
15  
16  // Public: Create a dev tools profile for a function.
17  //
18  // description - A {String} description that will be available in the Profiles
19  //               tab of the dev tools.
20  // fn - A {Function} to profile.
21  //
22  // Returns the value returned by the given function.
23  window.profile = function(description, fn) {
24    window.measure(description, function() {
25      console.profile(description);
26      let value = fn();
27      console.profileEnd(description);
28      return value;
29    });
30  };