Angular 2 - Observable to Promise失败

Question

I'm struggling with converting an observable into a promise. I know that there's the toPromise() function on any observable but when I use this function it returns me ZonedAwarePromise with the properties:

__zone_symbol_state: null and __zone_symbol_value: Array[0]

Also, the then part of the promise never gets fired.

Concrete Situation

I want to send an http-api-request that reads a file and returns its content inside the Promise:

public getData(fileName: string): Promise<any> {
    return new Promise( (resolve, reject) => {
        this.getHomeDirectory().then(homedir => {
            const fullFileName = homedir + fileName;
            const myApiRequest = "..." + fullFileName;
            return this.http.get(myApiRequest)
                        .map(this.extractData)
                        .toPromise()
                        .catch(this.handleError);
        });
    }
}

Calling this promise like so:

const fileName = '...';
this.fileService.getData(fileName).then( content => {
    console.log(content); // never gets fired!
});

I already tried different variations like replacing return with resolve(...) or Promise.resolve(...) and now I have no idea left how to fulfill this promise correctly in order to get the then part working.

Thank you in advance for any help and ideas!

Answer 1

in the new Promise callback you have to resolve :

 public getData(fileName: string): Promise<any> {
    return new Promise( (resolve, reject) => {
        this.getHomeDirectory().then(homedir => {
            const fullFileName = homedir + fileName;
            const myApiRequest = "..." + fullFileName;
            this.http.get(myApiRequest)
                        .map(this.extractData)
                        .catch(this.handleError)
                        .subsucribe(data =>  {
                            resolve(data )
                        });
        });
    }
}