Typescript 4.9 introduced a new keyword accessor to automatically make a property private and generate its accessors.

If I try to compile code that uses this keyword, I get the following error:

$ tsup src/index.ts --format esm --dts --clean
CLI Building entry: src/index.ts
CLI Using tsconfig: tsconfig.json
CLI tsup v6.6.3
CLI Target: es2022
CLI Cleaning output folder
ESM Build start
✘ [ERROR] Expected ";" but found "fieldName"

I rewrote my code to not use the keyword and it compiles perfectly.

Also, I compiled the code containing the keyword accessor using tsc and it is compiled properly.

So I suppose it's a compatibility issue with the last version of Typescript?