can log but unable to return value from addCallback

[hotani]

I can log the value, but it returns as "undefined".

var getOffice = function(county_id) {
var d = loadJSONDoc('/office_from_countytype/'+ county_id +'/');
var off_id;
d.addCallback(function (result) {
off_id=result[0].fields['office'];
log('got office id: '+ off_id);
return off_id;
});
}

The log entry will show "INFO: got office id: 14", but the function
returns "undefined".

[Fredrik]

You're confusing the return inside addCallback with the return from
the outer getOffice function.

--- modified example:
var getOffice = function(county_id) {
var d = loadJSONDoc('/office_from_countytype/'+ county_id +'/');
var off_id;
d.addCallback(function (result) {
off_id=result[0].fields['office'];
log('got office id: '+ off_id);
return off_id;
});
return d; // <--- !
}

... now, a user can get 'off_id' like this.

var d = getOffice(country_id);
d.addCallback(function(off_id) {
log('got office id:', off_id);
});

(since getOffice makes an asynchronous request any return from it
must, by definition, also be asynchronous.)

HTH
// Fredrik Blomqvist

Post by hotani
I can log the value, but it returns as "undefined".
var getOffice = function(county_id) {
    var d = loadJSONDoc('/office_from_countytype/'+ county_id +'/');
    var off_id;
    d.addCallback(function (result) {
        off_id=result[0].fields['office'];
        log('got office id: '+ off_id);
        return off_id;
    });
}
The log entry will show "INFO: got office id: 14", but the function
returns "undefined".

[hotani]

thanks for the response - I'll give this a try. I'm still trying to
wrap my head around the concepts of deferred and callbacks....

Post by Fredrik
You're confusing the return inside addCallback with the return from
the outer getOffice function.
var getOffice = function(county_id) {
    var d = loadJSONDoc('/office_from_countytype/'+ county_id +'/');
    var off_id;
    d.addCallback(function (result) {
        off_id=result[0].fields['office'];
        log('got office id: '+ off_id);
        return off_id;
    });
   return d; // <--- !
}
... now, a user can get 'off_id' like this.
var d = getOffice(country_id);
d.addCallback(function(off_id) {
    log('got office id:', off_id);
});
(since getOffice makes an asynchronous request any return from it
must, by definition, also be asynchronous.)
HTH
// Fredrik Blomqvist

Post by hotani
I can log the value, but it returns as "undefined".
var getOffice = function(county_id) {
    var d = loadJSONDoc('/office_from_countytype/'+ county_id +'/');
    var off_id;
    d.addCallback(function (result) {
        off_id=result[0].fields['office'];
        log('got office id: '+ off_id);
        return off_id;
    });
}
The log entry will show "INFO: got office id: 14", but the function
returns "undefined".