Performance API
When we're building sites and web apps, it's important to be able to measure the performance of our applications to help ensure good user experiences. We do this during development, testing stages, and in production. As our application grows and we add new features, it's equally important to make sure that the changes we're making aren't negatively affecting performance. There are a number of ways to measure this and some useful tools to help us. One such set of tools is the browser's Performance API and other closely related APIs.
The Performance API allows us to time events with extreme accuracy: the time measurements we have access to are expressed in milliseconds but are accurate to about 5 microseconds. With these APIs, we can accurately measure the time it takes to complete specific actions, such as the following:
- The time it took to render the first pixel on our page
- The time between a user clicking an element and...
