fs.writeFileSync passes the encoding the wrong way

[Borewit]

Failed to compile the project:

Running "ts:main" (ts) task
Compiling...
Using tsc v2.9.2
lib/index.ts(186,53): error TS2559: Type '"utf8"' has no properties in common with type '{ encoding?: string; mode?: string; flag?: string; }'.
lib/index.ts(427,44): error TS2559: Type '"utf8"' has no properties in common with type '{ encoding?: string; mode?: string; flag?: string; }'.

The gues the encoding should be passed wrapped in an option object.