WebStorm becomes very slow for any typescript files

typescript webstorm tsd

Old (2016-06)

Doing following helped me

Exclude dist folder and tmp folder so that webstorm will not search inside those.

Preferences->Directories->Excluded Folders

mannually

/Applications/WebStorm.app/Contents/bin/webstorm.vmoptions

or go to

Help/Edit VM Options

then change it to look

-Xms1024m

-Xmx1536m

-XX:MaxPermSize=1024m

-XX:ReservedCodeCacheSize=512m

-XX:+UseCompressedOops

Current Webstorm 2016.3.4 is quite good at angular, so if you have an old version first thing you need to do is to go for the latest version.
also if you are using an old angular-cli please update it as well because with angular 4 release they are focusing on more smaller build and faster typescript compilation.

Current Webstrom 2018.2 is exceptional with angular and I beleive if you are using this version and angular-cli version >= 6.1.2 you don't need to do any changes above