Chaining of asynchronous requests

Question

I need to do the asynchronous processing of data series (sending data to a REST server) and, only at the end of all requests, I need to perform another function.

How can I control this flow if each request is asynchronous?

What I need is something like this:

for (var i=0; l<objetos.length; i++){
  var o=objetos[i];
  Enviar($q, o).then(function(){})
}
//ao término de todas as requisições acima, disparar um novo evento...

Answer 1

I think it would be right to start a request only when another one is finished:

var enviarArquivo = function(indice)
{
    Enviar($q, objetos[indice]).then(function()
    {
        if (++indice < objetos.length)
        {
            enviarArquivo(indice);
        }
        else
        {
            // Processo finalizado
        }
    })
}

// Chamada inicial
enviarArquivo(0);

That way one request does not start without the other has finished and you can know when the last one is over.

Answer 2

you can use the $q. all to wait for all the

var promises = objetos.map(function (o) {
    return Enviar($q, o);
});

$q.all(promises).then(function(){});

recalling that the .then() returns a new promise, in which case you can perform an action at the end of sending each file and an action at the end of sending all the files.

var promises = objetos.map(function (o) {
    var promise = Enviar($q, o);
    return promise.then(function(){});
});

$q.all(promises).then(function(){});