This extension activates automatically when project's tsconfig.json file has "tstl" key.
Features
TypeScriptToLua Diagnostics
Sometimes, code that would normally be valid in JavaScript/TypeScript would be invalid when
transpiling to Lua. The TSTL extension will immediately warn you when this is the case, so that you
discover it at writing-time rather than at compile-time. For example:
Automatic tsconfig.json Schema
In most popular IDEs, you can specify a "$schema" key at the top of a JSON file. Doing this
activates auto-complete and field validation, which makes working with the JSON much easier.
One extra feature of VSCode is that if you happen to be working in a tsconfig.json file without
an explicitly defined "$schema" key, the editor will automatically use
the standard tsconfig schema.
If this extension detects a "tstl" key in the "tsconfig.json" file, then it will automatically
swap the schema to
one that includes the possible values for the "tstl" key.
This allows for auto-completing the TSTL properties: