Axios CancelToken vs AbortController: Which Cancellation Wins?

Cancellation priority when both signals are active

When an Axios request carries both a CancelToken source and an AbortController signal, the two mechanisms operate independently. Axios does not automatically propagate the AbortController signal to the CancelToken, nor vice versa. In practice, the cancellation that fires first takes effect: the request is aborted, and the associated promise rejects. The rejection reason's type--whether an Axios cancellation error or a DOMException--depends on which signal arrived first and on the execution environment. In browsers, AbortController targets the underlying XMLHttpRequest or fetch pipeline, while CancelToken uses Axios's internal abort logic. In Node.js (v15+), the same distinction holds, but Node's AbortController can integrate with native http.request when using the appropriate adapters, whereas CancelToken still relies on Axios's own cancellation machinery.

When both signals are present, the first trigger (by code order or environment timing) aborts the HTTP call; the second signal remains pending but has no effect on the in-flight request. The promise rejection carries an error whose properties differ: a CancelToken-induced rejection typically includes a reason string or Axios-internal code, while an AbortController-induced rejection yields a DOMException with a name and message. Neither error merges or suppresses the other; the losing signal simply becomes inert once the request terminates.

To verify which cancellation wins in your setup, follow these steps:

1. Create an Axios request with a CancelToken source using axios.CancelToken.source().
2. Attach an AbortController instance via the signal option.
3. Pass both the token and signal to the Axios call: axios.get(url, { cancelToken: source.token, signal: controller.signal })
4. Trigger the CancelToken source's cancel() method and record the promise rejection reason.
5. Trigger the AbortController's abort() method after the request has already been cancelled, if at all, and observe whether the rejection changes or persists.

To fully resolve which cancellation wins in your specific setup, I need to know: whether the request is running in a browser or Node.js environment, and which Axios version is in use. This detail changes the recommended diagnostic steps and whether deprecation warnings may appear.