Sorry that you are seeing this issue. Thank you for the files.
The problem is the fact that your system Node version is 8.x – a version that our internal tooling (that runs the editor functions like validation, content assist, etc.) won’t work with. Note that this constraint only exists for the version of Node used by our tooling – version 8.x can be used to create Angular projects, for instance.
Please go to Window > Preferences > Typescript, point to a Node.js version to anything < 8.x and the tooling should work as before.
Apologies for inconvenience caused. We’re working on adding support for this version in future releases.