Interface ExecResult

interface ExecResult {
    catch: <R = never>(
        onReject?: (err: ExecError) => R | PromiseLike<R>,
    ) => Promise<ExecOutput | R>;
    child: ChildProcess;
    promise: Promise<ExecOutput>;
    stderr: Readable;
    stdout: Readable;
    then: <T = ExecOutput, R = never>(
        onFulfill?: (output: ExecOutput) => T | PromiseLike<T>,
        onReject?: (err: ExecError) => R | PromiseLike<R>,
    ) => Promise<T | R>;
}