Tutorial

console.time() & console.timeEnd() in JavaScript

JavaScript

While this tutorial has content that we believe is of great benefit to our community, we have not yet tested or edited it to ensure you have an error-free learning experience. It's on our list, and we're working on it! You can help us out by using the "report an issue" button at the bottom of the tutorial.

The console object has time() and timeEnd() methods that help with analyzing performance of pieces of your code. You first call console.time() by providing a string argument, then the code that you want to test, then call console.timeEnd() with the same string argument. You’ll then see the time it took to run the code in your browser console. Here’s an example:

console.time("Time this");

for (var i = 0; i < 10000; i++) {
  // Your stuff here
}

console.timeEnd("Time this");

Most of the time code will execute too fast to be able to draw conclusions, so you’d most likely want to run your code in a for loop that goes through thousands of iterations.

Use this only in development mode and remove these calls in code that’s going into production.

Creative Commons License