12 min read

Performance , JavaScript , Coding , Techniques

The common rule of thumb is to never “block” the browser’s main thread when running JavaScript tasks. But is this a hard rule? Victor Ayomipo describes a use case he encountered involving a screenshot extension where he made an exception to the rule and decided that blocking the main thread was absolutely the right thing to do.

We’ve all heard of the sacred rule in modern web development, the rule never to be broken. The rule of “Never block the main thread.”

You almost can’t miss it as a web developer; it’s in almost every performance guide, and to be fair, it is good advice. We all know the browser’s main thread is single-threaded , meaning it can only do one thing at a time.

Plus, as we know, the main thread isn’t ours alone ; we share it with the browser’s rendering engine, input handlers, and other critical tasks. As a result, the less time we hold onto the main thread, the more responsive an app feels.…