我如何解决 mysql 中的抛出问题？

Question

I would like to resend again the (err) => { if (err) throw Error("error: insert client"); }, in the function that call it but the try catch dont works, i should use a promise? or a callback? because the function send mail its the same issue, and i think its more clear try to use the try catch like the first example, but im not sure. thanks for the help.

const somefunction = ( res, req ) => {
 try 
 {
   registerClient( 2, res.data);
   sendMail( "user@gmail.com", "welcome" );
 } 
 catch( e )
 { res.send( e ) }
}

const registerClient = (id, data) => {

  const time = new Date();

  const query =
    "INSERT INTO clientes( name, lastname, date, fk_user, type ) " +
    "VALUES ( ?, ?, ?, ?, 'client' )";

  connection.query(
    query,
    [data.name, data.lastname, time, id, ],
    (err) => {
      if (err) throw Error("error: insert client");
    }
  );
};

Answer 1

i should use a promise? or a callback?

Yes.

The try/catch block is sync, so it cannot catch an async throw.

In your code:

(err) => {
  if (err) throw Error("error: insert client");
}

The error "remains" inside the arrow function and it does not bubble up because it is executed in async (after the I/O to the database).

Here a callback example you can play with:

const somefunction = (res, req) => {
  registerClient(2, res.data, (err) => {
    if (err) {
      res.send(e)
    } else {
      sendMail('user@gmail.com', 'welcome') // fire and forget style (?)
      res.send('done')
    }
  })
}

const registerClient = (id, data, cb) => {
  const time = new Date()

  const query =
     'INSERT INTO clientes( name, lastname, date, fk_user, type ) ' +
     "VALUES ( ?, ?, ?, ?, 'client' )"

  connection.query(
    query,
    [data.name, data.lastname, time, id],
    cb
  )
}