When using file system events, this option specifies the polling strategy that gets used when the system runs out of native file watchers and/or doesn't support native file watchers.

• fixedPollingInterval: Check every file for changes several times a second at a fixed interval.
• priorityPollingInterval: Check every file for changes several times a second, but use heuristics to check certain types of files less frequently than others.
• dynamicPriorityPolling: Use a dynamic queue where less-frequently modified files will be checked less often.
• synchronousWatchDirectory: Disable deferred watching on directories. Deferred watching is useful when lots of file changes might occur at once (e.g. a change in node_modules from running npm install), but you might want to disable it with this flag for some less-common setups.