Wrong content-type used [serious bug]

I’ve manually set the content type to application/json before the axios.post() call.

Yet, when the request is made, it’s picking application/x-www-form-urlencoded huh? So I’ve added a transformRequest function and printed out the headers there:

You can see the JSON object for header, it’s has nested content types inside, for each method. It ignored the content type I’ve manually set.

If I add these code lines then it will work

// unset silly defaults
axios.defaults.headers.post = null
axios.defaults.headers.put = null

but that’s kinda silly and smells. A bug? I’ve read documentation carefully still am in the dark.

[avindra]

Update: I figured out when it happens.

So if the code tries to POST but the body isn’t set, axios resolves to that broken code path that is using the wrong header (picking from axios default rather than the configured options on the instance).

[avindra]

I’m having this issue and I’m not using transformRequest. My axiosInstance has been created as such:

  const instance = axios.create({
    baseURL: '/api/whatever',
    common: {
      'Content-Type': 'application/json',
      Accept: 'application/json',
    },
  });

Since common is set, I would expect the default to be application/json, but I’m seeing the issue @binarykitchen originally reported, where on some POST calls, the Content-Type is erroneously set to application/x-www-form-urlencoded.

Which POST calls is completely unknown to me. It appears to be random, but this is just code so I’m assuming there is a reproducible error condition.