TypeScript version is too low

[fgnosv]

The TypeScript lexer and parser versions are too low, so parsing is not possible when running open source. Please update typescript to the latest version.

[abulka]

Presumably you mean some newer (or merely current) Typescript syntax is not parsed properly? If so, I agree.

I'm not sure who is maintaining the Typescript grammar anymore. I contacted the two original authors of the grammar a while ago and they said they were no longer working on it.

[aleppard]

I've created a PR #3973 that upgrades the JavaScript part of TypeScript from the existing JavaScript grammar file, and adds a couple of Typescript improvements.

[aleppard]

I've created a new PR #3978 that upgrades it to v2.7. This is still far off the latest version of v5.3 or so; but it should be much more compatible with existing code.