DOMException

DOMException is the global error type used by Web APIs.

const error = new DOMException(
  "input is not valid base64",
  "InvalidCharacterError",
);

error.name;    // "InvalidCharacterError"
error.message; // "input is not valid base64"
error.code;    // 5
error instanceof Error; // true

The constructor accepts optional message and name strings and must be called with new. Instances inherit from Error.

Legacy code

code maps legacy names to their historical numeric values. Common examples include:

Unmapped names return 0. Legacy constants such as DOMException.ABORT_ERR are exposed on the constructor and prototype.

Abort, messaging, Fetch, Web Crypto, encoding, and base64 APIs use DOMException where their contracts require it.