How can I make a meteor callback that makes asynchronous calls?

Question

My client makes a call to the server.

Meteor.call('someRequest', params, onAllDoneCallback);

which is being processed (server code)

Meteor.methods({
    'someRequest': function(params, cb) {
        anAsyncFunction(params, cb);
        return true;
    },
});

I would like to onAllDoneCallbackstart on the client side after completion anAsyncFunctionand launch my own callback.

However, in Meteor it seems that the second argument is someRequestignored and that it onAllDoneCallbackstarts with the return someRequest, which is here trueand which is called before it anAsyncFunctionhas finished.

In my case, I'm more concerned about the synchronization problem (I use it to tell the client that the processing is complete, and not just that the request is well received), but others will probably want to call a callback with arguments from anAsyncFunction

Answer 1

. , . , , , . :

let Future = Npm.require('fibers/future');
Meteor.methods({
  someRequest: function (someArg) {
    // for security reasons, make sure you check the type of arguments.
    check(someArg, String);

    // future is an async handler.
    let future = new Future();
    // this is a function for a generic node style callback [ie, function (err, res)]
    let resolver = future.resolver();

    // run your function and pass it the future resolver
    // the future will be resolved when the callback happens.
    anAsyncFunction(someArg, resolver);

    // this meteor method will not end until future has been resolved.
    return future.wait();
  }
});

, Meteor wrapAsync, , . :

let wrappedAsyncFunction = Meteor.wrapAsync(anAsyncFunction /** second argument is `this` binding*/);
return wrappedAsyncFunction();

Answer 2

: : Meteor.wrapAsync

Meteor wrapAsync api, , , function(error, result){}. :

Meteor.methods({
    'someRequest': function(params){
        var wrap = Meteor.wrapAsync(anAsyncFunction);
        return wrap(params);
    },
});