Exception in catch block: TypeError: Response.text: Body has already been consumed.

[tgross35]

Description

If the error response is not JSON, this will raise a type error rather than returning the error body text.

Reproduction

Use the fetch API to hit an endpoint that returns a 4xx response with invalid JSON (i.e. plaintext). Based on debugging, the following is the issue:

    // handle errors (always parse as .json() or .text())
    let error = {};
    try {
      error = await response.json();
    } catch {
      error = await response.text();
    }

await response.json(); seems to first consume the body, then try parsing JSON. If reading the body succeeds but parsing the JSON fails, then the catch block will hit and response.text() will fail (since the body has already been consumed).

Expected result

error should probably still contain the error text, even if the response is non-JSON. I believe that the below would fix this:

    const text = await response.text();
    try {
      error = JSON.parse(text);
    } catch {
      error = text;
    }

Checklist

• I’m willing to open a PR (see CONTRIBUTING.md)

[drwpow]

Great catch! We had tests for unexpected responses for data, but not for error.

This would normally be a great issue for someone to pick up, but given this could break some sites and is a regression from the 0.9.0 version released earlier today, probably better to patch it sooner than later.

[tgross35]

Thanks for the quick fix!