Using typescript v2.3.4, the following code worked fine:
getStuff() : Promise<IStuff>{
return this.http.get(url, options)
.toPromise()
.then( (res) => {
let stuff: IStuff;
if (res.json().data){
stuff = res.json().data;
}
return stuff;
})
.catch( (reason) => {
this.handleError(reason);
});
}
...where handleError is like this:
handleError = (error:any) => {
this.debug(error);
throw error;
};
Now, with typescript v2.4.1 I get the error: 'Type 'Promise<void | IStuff>' is not assignable to type 'Promise<IStuff>'. Type 'void | IStuff' is not assignable to type 'IStuff'. Type 'void' is not assignable to type 'IStuff'.'
I can see why that would be the case.
...but this DOES work, and it makes no sense to me that it would work when the other code does not:
getStuff() : Promise<IStuff>{
return this.http.get(url, options)
.toPromise()
.then( (res) => {
let stuff: IStuff;
if (res.json().data){
stuff = res.json().data;
}
return stuff;
})
.catch( (reason) => {
if( reason.status) {
return Promise.reject(reason);
} else {
this.handleError(reason);
}
});
}
...in the else case, it is doing exactly what the code above that generates the error is doing, and yet there's no error.
I can fix the problem by just changing handleError to be:
handleError = (error:any):Promise<any> => {
this.debug(error);
Promise.reject(error);
};
...but I'm curious what the specific change was that caused this to become an error, and why does adding the if/else block work correctly when it has an else path that is identical to the original code?
