typescript-fetch: Properly detect and encode container request body param

[someone1]

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Description of the PR

Passing lists/containers to the body param as-is will send garbage via fetch - needed to stringify the contents first and only map over the items if it was a list of non-primitives.

fixes #3278

@TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @nicokoenig (2018/09) @topce (2018/10) @akehir (2019/07)

[macjohnny]

The body is a string now. Does this work correctly?

[someone1]

According to the Fetch API:

body: Any body that you want to add to your request: this can be a Blob, BufferSource, FormData, URLSearchParams, or USVString object. Note that a request using the GET or HEAD method cannot have a body.

Passing random objects and lists on my local results in a nonsense body value of [object Object]. I believe this has always been broken.

[macjohnny]

strange, but how can this

openapi-generator/samples/client/petstore/typescript-fetch/builds/default/apis/PetApi.ts

Line 95 in fae0738

body: PetToJSON(requestParameters.body),

work, it is also a object

[macjohnny]

it is converted here:

openapi-generator/samples/client/petstore/typescript-fetch/builds/default/runtime.ts

Lines 63 to 65 in fae0738

	const body = (context.body instanceof FormData || isBlob(context.body))
	? context.body
	: JSON.stringify(context.body);

so JSON.stringify is not necessary here

[someone1]

I see - did not catch that, thanks!

[macjohnny]

LGTM

[wing328]

@someone1 thanks for the PR, which has been included in the 4.1.0 release: https://twitter.com/oas_generator/status/1160000504455319553