Warn if formData hash values are not strings, to prevent source.on is not a function

[nhooey]

In request/request#1495, the example code gets an error like source.on is not a function because one of the values in the formData has for a request or request-promise options hash is not a string.

The form-data module should detect this error and tell the user to ensure all formdata hash values are strings, or writeStreams, or whatever else is valid.

[alexindigo]

Yeah, looks like legit issue. Do you mind to create a PR? Thank you

[nhooey]

@alexindigo That was four months ago. I'm not using the library anymore...

[alexindigo]

Ok. I'll close this issue then. :) Thanks.

[nhooey]

Why would you close an issue without a solution?

[alexindigo]

You said, you're no longer interested in this issue. So it was logical to close it.
Please let me know if/when you want to get back to it. Thank you.

[nhooey]

I meant that I can't really make a pull request for it.

It's still an issue potentially to a lot of people, even if they don't complain about it. It's an instance where the code doesn't check its inputs, which is a defect.

[nhooey]

I'd suggest leaving it open so we can track the defect.

[alexindigo]

Ok.

[nhooey]

Thanks @alexindigo!

[DylanPiercey]

I'll take a look at this when we do #137.

[DylanPiercey]

Closing as a duplicate of #137.
Work is being done in #362.

[DylanPiercey]

Also, specifically for converting objects to use formdata syntax see q-flat.