const { core } = Deno; class DOMException { constructor(message, code) { this.msg = message; this.code = code; } } core.registerErrorBuilder( "DOMExceptionOperationError", function DOMExceptionOperationError(msg) { return new DOMException(msg, "OperationError"); }, ); try { core.opSync("op_err", undefined, null); throw new Error("op_err didn't throw!"); } catch (err) { if (!(err instanceof DOMException)) { throw new Error("err not DOMException"); } if (err.msg !== "abc") { throw new Error("err.message is incorrect"); } if (err.code !== "OperationError") { throw new Error("err.code is incorrect"); } }