AbortError

AbortError is an error type used in web platform APIs to signal that an operation was canceled. It is represented as a DOMException with the name AbortError. The message is often "The operation was aborted," but implementations may vary.

The cancellation mechanism relies on AbortController and AbortSignal. An AbortController instance provides a signal that can be passed to asynchronous APIs such as fetch, ReadableStream, or WebCrypto operations. Calling abort() on the controller triggers cancellation of the associated operation, causing it to reject or throw an AbortError.

In practice, fetch will reject its promise with an AbortError when the request is aborted via the signal. Other APIs that honor the signal may also throw or reject with AbortError, depending on the operation and environment.

Handling AbortError typically involves catching the error and distinguishing it from other failures. A common pattern is to check the error name—if err.name is "AbortError," the cancellation can be treated as a normal control flow event rather than a failure, while other errors are handled separately.

Notes and caveats: AbortError is not necessarily fatal; it indicates deliberate cancellation. Support for AbortController and AbortSignal is widespread in modern browsers and in many JavaScript environments, but older environments may lack this mechanism, in which case cancellation may be implemented differently or not at all. Some libraries may polyfill AbortController, producing a DOMException with the AbortError name to maintain a consistent interface.

See also: AbortController, AbortSignal, DOMException, Fetch API, cancellation patterns in asynchronous JavaScript.