Node.js ENFILE/EMFILE -- too many open files

Node.js crashes with EMFILE during bulk file operations or in file-watching tools.

Increase limit: ulimit -n 65536. Use graceful-fs. Limit concurrency with p-limit. For watchers: use ignored patterns to reduce watched files.

OS limits file descriptors per process. Default (1024) is too low for dev tools watching large projects.