Promises & TypeScript
up vote
1
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I have a method that I must implement through an abstract class, which has a signature like this:
isAuthenticated(path: string): boolean
In the implementation I'm calling a promise from an authorization server
isAuthenticated(path: string): boolean {
this.authorization.isAuthenticated().then((res) => {
if(res == true) {
return true;
}
return false;
});
}
But the method gives me a error/warning like this:
A function whose type is neither declared type is neither 'void' nor 'any' must return a value
typescript promise angular6
asked Nov 20 at 14:57
Tom Kurian
358
add a comment |
up vote
1
down vote
favorite
I have a method that I must implement through an abstract class, which has a signature like this:
isAuthenticated(path: string): boolean
In the implementation I'm calling a promise from an authorization server
isAuthenticated(path: string): boolean {
this.authorization.isAuthenticated().then((res) => {
if(res == true) {
return true;
}
return false;
});
}
But the method gives me a error/warning like this:
A function whose type is neither declared type is neither 'void' nor 'any' must return a value
typescript promise angular6
asked Nov 20 at 14:57
Tom Kurian
358
your promise return something in your function. you need to return the result with maybereturn this.authorisation....
– charles Lgn
Nov 20 at 14:59
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I have a method that I must implement through an abstract class, which has a signature like this:
isAuthenticated(path: string): boolean
In the implementation I'm calling a promise from an authorization server
isAuthenticated(path: string): boolean {
this.authorization.isAuthenticated().then((res) => {
if(res == true) {
return true;
}
return false;
});
}
But the method gives me a error/warning like this:
A function whose type is neither declared type is neither 'void' nor 'any' must return a value
typescript promise angular6
asked Nov 20 at 14:57
Tom Kurian
358
I have a method that I must implement through an abstract class, which has a signature like this:
isAuthenticated(path: string): boolean
In the implementation I'm calling a promise from an authorization server
isAuthenticated(path: string): boolean {
this.authorization.isAuthenticated().then((res) => {
if(res == true) {
return true;
}
return false;
});
}
But the method gives me a error/warning like this:
A function whose type is neither declared type is neither 'void' nor 'any' must return a value
typescript promise angular6
typescript promise angular6
asked Nov 20 at 14:57
Tom Kurian
358
asked Nov 20 at 14:57
Tom Kurian
358
asked Nov 20 at 14:57
Tom Kurian
358
asked Nov 20 at 14:57
Tom Kurian
358
asked Nov 20 at 14:57
Tom Kurian
358
358
your promise return something in your function. you need to return the result with maybereturn this.authorisation....
– charles Lgn
Nov 20 at 14:59
add a comment |
your promise return something in your function. you need to return the result with maybereturn this.authorisation....
– charles Lgn
Nov 20 at 14:59
your promise return something in your function. you need to return the result with maybe
return this.authorisation....– charles Lgn
Nov 20 at 14:59
your promise return something in your function. you need to return the result with maybe
return this.authorisation....– charles Lgn
Nov 20 at 14:59
add a comment |
1 Answer
1
active
oldest
votes
up vote
1
down vote
You are not returning anything from isAuthenticated. You also cannot just "wait" here for the result that simply.
You can do this:
isAuthenticated(path: string): Promise<boolean> {
// return the ".then" to return a promise of the type returned
// in the .then
return this.authorization.isAuthenticated().then((res) => {
if(res === true) {
return true;
}
return false;
});
}
And allow the caller to "wait" for the boolean result.
Note: Assuming that this.authorization.isAuthenticated returns a Promise<boolean> and you don't need to do any other actions in the .then, the code could be simplified to:
isAuthenticated(path: string): Promise<boolean> {
return this.authorization.isAuthenticated();
}
answered Nov 20 at 15:01
crashmstr
23.5k65174
1
You could also use async/wait typescriptlang.org/play/…
– Titian Cernicova-Dragomir
Nov 20 at 15:05
@JohnnyHK Probably, but I did not want to assume too much or change too much from what they had. But I did realize that the.thenis probably unnecessary.
– crashmstr
Nov 20 at 15:06
@TitianCernicova-Dragomir Yes. Not as familiar yet with that syntax, but the ultimate point is that the code won't stop and wait for the result: you need to have the caller "wait" for it with some syntax.
– crashmstr
Nov 20 at 15:08
Thanks! But the problem is that I'm implementing an abstract method that just returns a boolean not Promise<boolean>.
– Tom Kurian
Nov 20 at 15:21
@TomKurian Sincethis.authorization.isAuthenticatedreturns a promise, you can only get the boolean result by.then,awaitin anasyncfunction, or a callback function. All of which will be completed asynchronously. Thus, there is no way of returning "just a boolean" from this function.
– crashmstr
Nov 20 at 15:24
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
You are not returning anything from isAuthenticated. You also cannot just "wait" here for the result that simply.
You can do this:
isAuthenticated(path: string): Promise<boolean> {
// return the ".then" to return a promise of the type returned
// in the .then
return this.authorization.isAuthenticated().then((res) => {
if(res === true) {
return true;
}
return false;
});
}
And allow the caller to "wait" for the boolean result.
Note: Assuming that this.authorization.isAuthenticated returns a Promise<boolean> and you don't need to do any other actions in the .then, the code could be simplified to:
isAuthenticated(path: string): Promise<boolean> {
return this.authorization.isAuthenticated();
}
answered Nov 20 at 15:01
crashmstr
23.5k65174
1
You could also use async/wait typescriptlang.org/play/…
– Titian Cernicova-Dragomir
Nov 20 at 15:05
@JohnnyHK Probably, but I did not want to assume too much or change too much from what they had. But I did realize that the.thenis probably unnecessary.
– crashmstr
Nov 20 at 15:06
@TitianCernicova-Dragomir Yes. Not as familiar yet with that syntax, but the ultimate point is that the code won't stop and wait for the result: you need to have the caller "wait" for it with some syntax.
– crashmstr
Nov 20 at 15:08
Thanks! But the problem is that I'm implementing an abstract method that just returns a boolean not Promise<boolean>.
– Tom Kurian
Nov 20 at 15:21
@TomKurian Sincethis.authorization.isAuthenticatedreturns a promise, you can only get the boolean result by.then,awaitin anasyncfunction, or a callback function. All of which will be completed asynchronously. Thus, there is no way of returning "just a boolean" from this function.
– crashmstr
Nov 20 at 15:24
add a comment |
up vote
1
down vote
You are not returning anything from isAuthenticated. You also cannot just "wait" here for the result that simply.
You can do this:
isAuthenticated(path: string): Promise<boolean> {
// return the ".then" to return a promise of the type returned
// in the .then
return this.authorization.isAuthenticated().then((res) => {
if(res === true) {
return true;
}
return false;
});
}
And allow the caller to "wait" for the boolean result.
Note: Assuming that this.authorization.isAuthenticated returns a Promise<boolean> and you don't need to do any other actions in the .then, the code could be simplified to:
isAuthenticated(path: string): Promise<boolean> {
return this.authorization.isAuthenticated();
}
answered Nov 20 at 15:01
crashmstr
23.5k65174
1
You could also use async/wait typescriptlang.org/play/…
– Titian Cernicova-Dragomir
Nov 20 at 15:05
@JohnnyHK Probably, but I did not want to assume too much or change too much from what they had. But I did realize that the.thenis probably unnecessary.
– crashmstr
Nov 20 at 15:06
@TitianCernicova-Dragomir Yes. Not as familiar yet with that syntax, but the ultimate point is that the code won't stop and wait for the result: you need to have the caller "wait" for it with some syntax.
– crashmstr
Nov 20 at 15:08
Thanks! But the problem is that I'm implementing an abstract method that just returns a boolean not Promise<boolean>.
– Tom Kurian
Nov 20 at 15:21
@TomKurian Sincethis.authorization.isAuthenticatedreturns a promise, you can only get the boolean result by.then,awaitin anasyncfunction, or a callback function. All of which will be completed asynchronously. Thus, there is no way of returning "just a boolean" from this function.
– crashmstr
Nov 20 at 15:24
add a comment |
up vote
1
down vote
up vote
1
down vote
You are not returning anything from isAuthenticated. You also cannot just "wait" here for the result that simply.
You can do this:
isAuthenticated(path: string): Promise<boolean> {
// return the ".then" to return a promise of the type returned
// in the .then
return this.authorization.isAuthenticated().then((res) => {
if(res === true) {
return true;
}
return false;
});
}
And allow the caller to "wait" for the boolean result.
Note: Assuming that this.authorization.isAuthenticated returns a Promise<boolean> and you don't need to do any other actions in the .then, the code could be simplified to:
isAuthenticated(path: string): Promise<boolean> {
return this.authorization.isAuthenticated();
}
answered Nov 20 at 15:01
crashmstr
23.5k65174
You are not returning anything from isAuthenticated. You also cannot just "wait" here for the result that simply.
You can do this:
isAuthenticated(path: string): Promise<boolean> {
// return the ".then" to return a promise of the type returned
// in the .then
return this.authorization.isAuthenticated().then((res) => {
if(res === true) {
return true;
}
return false;
});
}
And allow the caller to "wait" for the boolean result.
Note: Assuming that this.authorization.isAuthenticated returns a Promise<boolean> and you don't need to do any other actions in the .then, the code could be simplified to:
isAuthenticated(path: string): Promise<boolean> {
return this.authorization.isAuthenticated();
}
answered Nov 20 at 15:01
crashmstr
23.5k65174
edited Nov 20 at 15:10
answered Nov 20 at 15:01
crashmstr
23.5k65174
answered Nov 20 at 15:01
crashmstr
23.5k65174
answered Nov 20 at 15:01
crashmstr
23.5k65174
23.5k65174
1
You could also use async/wait typescriptlang.org/play/…
– Titian Cernicova-Dragomir
Nov 20 at 15:05
@JohnnyHK Probably, but I did not want to assume too much or change too much from what they had. But I did realize that the.thenis probably unnecessary.
– crashmstr
Nov 20 at 15:06
@TitianCernicova-Dragomir Yes. Not as familiar yet with that syntax, but the ultimate point is that the code won't stop and wait for the result: you need to have the caller "wait" for it with some syntax.
– crashmstr
Nov 20 at 15:08
Thanks! But the problem is that I'm implementing an abstract method that just returns a boolean not Promise<boolean>.
– Tom Kurian
Nov 20 at 15:21
@TomKurian Sincethis.authorization.isAuthenticatedreturns a promise, you can only get the boolean result by.then,awaitin anasyncfunction, or a callback function. All of which will be completed asynchronously. Thus, there is no way of returning "just a boolean" from this function.
– crashmstr
Nov 20 at 15:24
add a comment |
1
You could also use async/wait typescriptlang.org/play/…
– Titian Cernicova-Dragomir
Nov 20 at 15:05
@JohnnyHK Probably, but I did not want to assume too much or change too much from what they had. But I did realize that the.thenis probably unnecessary.
– crashmstr
Nov 20 at 15:06
@TitianCernicova-Dragomir Yes. Not as familiar yet with that syntax, but the ultimate point is that the code won't stop and wait for the result: you need to have the caller "wait" for it with some syntax.
– crashmstr
Nov 20 at 15:08
Thanks! But the problem is that I'm implementing an abstract method that just returns a boolean not Promise<boolean>.
– Tom Kurian
Nov 20 at 15:21
@TomKurian Sincethis.authorization.isAuthenticatedreturns a promise, you can only get the boolean result by.then,awaitin anasyncfunction, or a callback function. All of which will be completed asynchronously. Thus, there is no way of returning "just a boolean" from this function.
– crashmstr
Nov 20 at 15:24
1
1
You could also use async/wait typescriptlang.org/play/…
– Titian Cernicova-Dragomir
Nov 20 at 15:05
You could also use async/wait typescriptlang.org/play/…
– Titian Cernicova-Dragomir
Nov 20 at 15:05
@JohnnyHK Probably, but I did not want to assume too much or change too much from what they had. But I did realize that the
.then is probably unnecessary.– crashmstr
Nov 20 at 15:06
@JohnnyHK Probably, but I did not want to assume too much or change too much from what they had. But I did realize that the
.then is probably unnecessary.– crashmstr
Nov 20 at 15:06
@TitianCernicova-Dragomir Yes. Not as familiar yet with that syntax, but the ultimate point is that the code won't stop and wait for the result: you need to have the caller "wait" for it with some syntax.
– crashmstr
Nov 20 at 15:08
@TitianCernicova-Dragomir Yes. Not as familiar yet with that syntax, but the ultimate point is that the code won't stop and wait for the result: you need to have the caller "wait" for it with some syntax.
– crashmstr
Nov 20 at 15:08
Thanks! But the problem is that I'm implementing an abstract method that just returns a boolean not Promise<boolean>.
– Tom Kurian
Nov 20 at 15:21
Thanks! But the problem is that I'm implementing an abstract method that just returns a boolean not Promise<boolean>.
– Tom Kurian
Nov 20 at 15:21
@TomKurian Since
this.authorization.isAuthenticated returns a promise, you can only get the boolean result by .then, await in an async function, or a callback function. All of which will be completed asynchronously. Thus, there is no way of returning "just a boolean" from this function.– crashmstr
Nov 20 at 15:24
@TomKurian Since
this.authorization.isAuthenticated returns a promise, you can only get the boolean result by .then, await in an async function, or a callback function. All of which will be completed asynchronously. Thus, there is no way of returning "just a boolean" from this function.– crashmstr
Nov 20 at 15:24
add a comment |
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your promise return something in your function. you need to return the result with maybe
return this.authorisation....– charles Lgn
Nov 20 at 14:59