- Network cost: More memory equates to longer downloads
- Parse and compile cost: JS is parsed and compiled on the main thread. When there is a hiccup on the main thread, the more time elapses before user input can be taken.
- Execution cost: The more JS being executed in the main thread, the longer it takes to get to Time To Interactive (TTI).
- Memory cost: If JS uses a large quantity of references, the more memory it could take up. Large amounts of memory download can slow pages and memory leaks potentially can freeze the page.
- Use code splitting to only parse code your users actually need.
- Minify and compress code whenever possible.
- Delete unused code.
- Cache code with the PRPL pattern.