browser: `setInputFiles` documentation and behavior mismatch

[lvogt]

Brief summary

The documentation and typings for setInputFiles is wrong twice

k6 version

v0.57.0

OS

all

Docker version and image (if applicable)

No response

Steps to reproduce the problem

Create any k6 script in Typescript with types provided by the @types/k6 package. The File interface from the k6/browser has two incorrect typings:

• The mime type parameter is named in camel case (mimeType) but k6 actually expects all lowercase mimetype
• The buffer parameter is typed as ArrayBuffer but string containing the base64 encoded data is expected

(The sample script in the documentation is actually correct btw)

Expected behaviour

The typings/documentation match and everything works.

Actual behaviour

You get either errors from the typescript compiler (due to mismatch ArrayBuffer vs string or mimeType vs mimetype) or issues during test execution (exceptions when the injected script tries to decode the ArrayBuffer with atob or missing mime type)

[lvogt]

At first I wanted to create a pull request at DefinitelyTyped to fix this. But I am not sure if you rather want to keep the types as is but fix the k6 go code?

[codebien]

@inancgumus can you help here, please? What is the expectation?

[inancgumus]

@codebien I'd suggest you look at the following links I've collected for you so that you can check if there are any mismatches and incorrect behavior in the browser API and docs:

• Typescript: File is used by setInputFiles.
• Docs: Page.setInputFiles
• Code: File option.
• Code: Page.setInputFiles mapping.
• Code: setInputFiles main code.

Let me know if you have other questions 🙇

[JunNishimura]

@inancgumus

Hi,

Regarding this issue, I took the approach of changing the type of the buffer property of the File interface to string.

I would appreciate if you check and review the PRs.

grafana/k6-DefinitelyTyped#115
grafana/k6-docs#2205

Thanks

[JunNishimura]

The description regarding mimeType mentioned in this issue has already been resolved, so I didn't do anything about the mimeType property.

[joanlopez]

@inancgumus @codebien what's the agreement here?

Do we really want to change docs/types, or should we change k6 instead?
I know Playwright compatibility isn't our main goal, but I still think that using something else other than string but like ArrayBuffer would provide much better API ergonomics.

What do you think?

cc/ @JunNishimura (let's wait for reaching an agreement before moving forward with PR reviews)