Let us use an example:
var q = require('q');
var myAsyncFunction = function(err, result) {
if (err)
console.log("We got an error");
console.log("Success");
};
myAsyncFunction().then(function () { console.log("promise is working");
});
myAsyncFunction().then(function () { console.log("it really worked"); });
^
TypeError: Cannot call method 'then' of undefined
How do I turn myAsyncFunction into a promise?
On Monday, October 21, 2013 10:58:34 AM UTC-7, Mariusz Nowak wrote:
>
>
> On 21 paź 2013, at 19:52, Reza Razavipour <[email protected]<javascript:>>
> wrote:
>
> we all of this I still can not figure out how to take an async function
> and change it from callback to a promise.
>
>
>
> Many libraries provide it's own utils for that, just check their
> documentation:
>
> https://github.com/kriskowal/q#adapting-node
>
> https://github.com/medikoo/deferred#promisify---working-with-asynchronous-functions-as-we-know-them-from-nodejs
>
> https://github.com/petkaantonov/bluebird/blob/master/API.md#promisepromisifyfunction-nodefunction--dynamic-receiver---function
>
>
>
> 1. Do I have to declare a promise before I can call a 'then' on it? Every
> time I do not and call a then on an async function, I get a syntax error.
>
>
>
> On Friday, October 18, 2013 3:11:47 PM UTC-7, Reza Razavipour wrote:
>>
>> I am a fairly new to javaScript and node.js both.
>>
>> I am trying to wrap my head around promises and I am having a hard time.
>> I am looking for a very simple tutorial/video on this topic and having
>> little success.
>>
>> Is there a reference that can be recommended? A before and after code
>> snippet can be a good starting position.
>>
>> Reza
>>
>>
>>
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