More strict isFormDataLike

[ronag]

isFormDataLike currently only checks that the constructor.name is 'FormData'. We should also check the interface as there are npm packages that have the correct name but wrong interface causing confusion where it's read as a FOrmData instead of a async generator..

[ronag]

https://www.npmjs.com/package/form-data

[mateonunez]

Hey @ronag, what about the following check?

function isFormDataLike (chunk) {
  return (
    (chunk &&
      chunk.constructor && chunk.constructor.name === 'FormData' &&
      /^(FormData)$/.test(chunk[Symbol.toStringTag])
    )
  )
}

Could this control be sufficient in your opinion? It checks if the instance of chunk contains the Symbol.toStringTag. It's extendible with other thirds parts (ex: formdata-node) and prevents confusion between packages like: form-data.

[ronag]

I'm not sure that is sufficient

[ronag]

That has the problem in the other direction. Third party module that are FormData like might not work. I think it's best to check constructor.name and make sure the expected API is available on the instance.