Value is always undefined returning from promise

Question

I am currently working with the blackberry dynamics SDK.

I am currently using the http request functionality for the SDK but every time I want to return a response from a http call its always undefined - I tried promisifying it to return a value but to no avail.

It originally used two callbacks - which would rightly return me undefined, but if I make it a promise should it not return me a value.

Code

function constructGDHttpPostRequest(reqObj) {
    let PostRequest = window.plugins.GDHttpRequest.createRequest("POST", URI + reqObj.endPoint, 30, false);
    PostRequest.addRequestHeader('Content-Type', 'application/json');
    PostRequest.addHttpBody(reqObj.body);
    return SendRequest(PostRequest).then(function (httpRes) {
        console.log(httpRes);
        return httpRes;
    })
}

function SendRequest(Request) {
    return new Promise(function (resolve) {
        resolve(Request.send(sendSuccess));
    })
}

function sendSuccess(response) {
    console.log("Received valid response from the send request");
    let Response = window.plugins.GDHttpRequest.parseHttpResponse(response);
    return JSON.parse(Response.responseText);
}

I have tried using some of the questions asked relating to something like this but it still returned undefined from the promise.

Cheers in advance.

See https://stackoverflow.com/questions/23803743/what-is-the-explicit-promise-construction-antipattern-and-how-do-i-avoid-it — Benjamin Gruenbaum, Nov 26 '18 at 15:48
I know there unnecessary - I have just been sticking a bunch in because I cant get anything returning from sendSuccess — Studento919, Nov 26 '18 at 15:52
Regardless `console.log(httpRes);` still returns undefined no matter what I do. — Studento919, Nov 26 '18 at 16:05
you should `resolve` when the `sendSuccess` callback is actually called. That is the time to resolve the promise NOT resolve on initiating the request — Nikos M., Nov 26 '18 at 16:13

score 0 · Accepted Answer · answered Nov 26 '18 at 17:01

As per @Nikos M. suggestion this is what ave done and now works as expected.

I needed to resolve the callback in order to return a value.

I would like to make the callback a little cleaner with some suggestions.

   function constructGDHttpPostRequest(reqObj) {
        let PostRequest = window.plugins.GDHttpRequest.createRequest("POST", URI + reqObj.endPoint, 30, false);
        PostRequest.addRequestHeader('Content-Type', 'application/json');
        PostRequest.addHttpBody(reqObj.body);
        return SendRequest(PostRequest).then(function (httpRes) {
            console.log(httpRes);
            return httpRes;
        })
    }

    function SendRequest(Request) {
        return new Promise(function (resolve) {
            Request.send(function (response) {
                resolve(JSON.parse(window.plugins.GDHttpRequest.parseHttpResponse(response).responseText));
            });
        })
    }

Value is always undefined returning from promise

1 Answers1