TypeError: body used already for - should be able to extract twice

I unfortunately am calling a service which may or may not return JSON (or any) body data.

When I do the following, I get the TypeError: body used already for error:

let data = null

try {
  data = await res.json()
} catch (e) {
  data = await res.text()
}

Two things:

• I should be able to call .json() / .text() multiple times
• If the body is empty, it should just return null instead of throwing on .text()

[arthakdoo]

The use-case from the beginning of the post is, imho, very normal and should be supported. I have just tried doing literally the same thing, and I believe many people think the same (probably because we are used to that try { JSON.parse } catch {} paradigm. It is not relevant to consumers of the library that there is some underlying stream etc. as implementation. This should work, all I’m saying…

[jimmywarting]

the alternetive is that you only use .text() and then try to parse the json into a object using JSON.parse(text)

Maybe also worth having a look at some of the headers you get back. eg content-length, content-type that match application/json look also if res.ok is true or false before you continue down the path