May 20, 2023
Purpose and Usage
Long Tasks can occur for a variety of reasons. Some common causes include large amounts of data being processed, complex algorithms being run, or third-party scripts taking longer to execute than expected. Long Tasks can be particularly problematic on mobile devices or older computers that have slower processing speeds.
The impact of Long Tasks on a website’s performance can be significant. When a Long Task is executing, the browser’s main thread is blocked, which means that other tasks cannot be executed until the Long Task is complete. This can lead to slow and unresponsive UI, which can frustrate users and lead them to abandon the website.
To combat the negative effects of Long Tasks, developers can use various tools and techniques to identify and optimize them. The first step is to monitor a website’s performance using tools like the Chrome DevTools Performance tab or the Lighthouse performance audit. These tools can provide insights into which scripts are causing Long Tasks and how long they are taking to execute.
Once Long Tasks have been identified, developers can take steps to optimize them. Some common optimization techniques include:
Lazy loading: This involves delaying the loading of non-critical resources until they are needed. By doing so, developers can prevent the browser from getting bogged down with unnecessary tasks and keep the main thread free for more important tasks.
Caching: This involves storing frequently accessed data in the browser’s cache to prevent the need for repeated server requests. By doing so, developers can reduce the amount of code that needs to be executed, which can reduce the likelihood of Long Tasks occurring.