export async function asynctryexpr<T>(cb: () => Promise<T>): Promise<[ Error, null ] | [ null, T ]> {
  try {
    const val = await cb();
    return [ null, val ];
  } catch(e) {
    if(e instanceof Error) return [ e, null ];
    return [ new Error(`${e}`), null ];
  }
}

export function tryexpr<T>(cb: () => T): [ Error, null ] | [ null, T ] {
  try {
    const val = cb();
    return [ null, val ];
  } catch(e) {
    if(e instanceof Error) return [ e, null ];
    return [ new Error(`${e}`), null ];
  }
}