The documentation here https://cloud.google.com/vision/docs/supported-files states PDF & TIFF are supported. Using the Node.js client library I get an error response code:3 & message:'Bad image data.' for TIFFs and PDFs but all other file types are accepted and labeled. I'm using local files not cloud storage e.g.
const [result] = await client.labelDetection('./test.pdf');
Neither of the "Try it!" demo pages will allow upload of TIFF or PDF either.