- A cancelled request is rejected with an [`AbortError`](https://github.com/node-fetch/node-fetch/blob/master/README.md#class-aborterror). You can check if the reason for rejection was that the request was aborted by checking the `Error`'s `name` is `AbortError`.
- All [operational errors][joyent-guide] *other than aborted requests* are rejected with a [FetchError](https://github.com/node-fetch/node-fetch/blob/master/README.md#class-fetcherror). You can handle them all through the `try/catch` block or promise `catch` clause.
- All errors originating from Node.js core are marked with `error.type = 'system'`, and in addition contain an `error.code` and an `error.errno` for error handling. These are aliases for error codes thrown by Node.js core.
- [Programmer errors][joyent-guide] are either thrown as soon as possible, or rejected with default `Error` with `error.message` for ease of troubleshooting.
- Because we maintain 100% coverage, see [test/main.js](https://github.com/node-fetch/node-fetch/blob/master/test/main.js) for a full list of custom `FetchError` types, as well as some of the common errors from Node.js