Can a Descriptor change type in Typescript?
1
I'm trying to make descriptor which can change return type in typescript but I don't know how to do this.
Here is the code and what I tried:
function changeReturnType()
{
return <T extends unknown>(
target: {},
key: string | symbol,
descriptor: TypedPropertyDescriptor<T>
) => {
const oldValue = descriptor.value;
return {
...descriptor,
value(...argv)
{
// @ts-ignore
return String(oldValue.call(target, ...argv))
}
}
};
}
class Foo {
@changeReturnType()
square ()
{
return 1;
}
}
let val = new Foo().square(); // I hope ts know here is string
console.dir({
val,
type: typeof val,
});
javascript node.js typescript types descriptor
edited Nov 11 at 7:15
Roy Scheffers
2,15291725
asked Nov 11 at 6:06
bluelovers
1538
add a comment |
1
I'm trying to make descriptor which can change return type in typescript but I don't know how to do this.
Here is the code and what I tried:
function changeReturnType()
{
return <T extends unknown>(
target: {},
key: string | symbol,
descriptor: TypedPropertyDescriptor<T>
) => {
const oldValue = descriptor.value;
return {
...descriptor,
value(...argv)
{
// @ts-ignore
return String(oldValue.call(target, ...argv))
}
}
};
}
class Foo {
@changeReturnType()
square ()
{
return 1;
}
}
let val = new Foo().square(); // I hope ts know here is string
console.dir({
val,
type: typeof val,
});
javascript node.js typescript types descriptor
edited Nov 11 at 7:15
Roy Scheffers
2,15291725
asked Nov 11 at 6:06
bluelovers
1538
add a comment |
1
1
1
1
I'm trying to make descriptor which can change return type in typescript but I don't know how to do this.
Here is the code and what I tried:
function changeReturnType()
{
return <T extends unknown>(
target: {},
key: string | symbol,
descriptor: TypedPropertyDescriptor<T>
) => {
const oldValue = descriptor.value;
return {
...descriptor,
value(...argv)
{
// @ts-ignore
return String(oldValue.call(target, ...argv))
}
}
};
}
class Foo {
@changeReturnType()
square ()
{
return 1;
}
}
let val = new Foo().square(); // I hope ts know here is string
console.dir({
val,
type: typeof val,
});
javascript node.js typescript types descriptor
edited Nov 11 at 7:15
Roy Scheffers
2,15291725
asked Nov 11 at 6:06
bluelovers
1538
I'm trying to make descriptor which can change return type in typescript but I don't know how to do this.
Here is the code and what I tried:
function changeReturnType()
{
return <T extends unknown>(
target: {},
key: string | symbol,
descriptor: TypedPropertyDescriptor<T>
) => {
const oldValue = descriptor.value;
return {
...descriptor,
value(...argv)
{
// @ts-ignore
return String(oldValue.call(target, ...argv))
}
}
};
}
class Foo {
@changeReturnType()
square ()
{
return 1;
}
}
let val = new Foo().square(); // I hope ts know here is string
console.dir({
val,
type: typeof val,
});
javascript node.js typescript types descriptor
javascript node.js typescript types descriptor
edited Nov 11 at 7:15
Roy Scheffers
2,15291725
asked Nov 11 at 6:06
bluelovers
1538
edited Nov 11 at 7:15
Roy Scheffers
2,15291725
asked Nov 11 at 6:06
bluelovers
1538
edited Nov 11 at 7:15
Roy Scheffers
2,15291725
edited Nov 11 at 7:15
Roy Scheffers
2,15291725
edited Nov 11 at 7:15
Roy Scheffers
2,15291725
2,15291725
asked Nov 11 at 6:06
bluelovers
1538
asked Nov 11 at 6:06
bluelovers
1538
asked Nov 11 at 6:06
bluelovers
1538
1538
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
0
This is currently not possible in TypeScript but you may look at this comment and modify hack described there to your needs (i.e. for method decorator usage).
answered Nov 11 at 10:10
syntagma
12.5k1248104
The situation is different in linked comment. Returned type is ignored in class decorator, while in method decorator it's taken into account, so decorated method type is incompatible with original method.
– estus
Nov 11 at 15:32
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
0
This is currently not possible in TypeScript but you may look at this comment and modify hack described there to your needs (i.e. for method decorator usage).
answered Nov 11 at 10:10
syntagma
12.5k1248104
The situation is different in linked comment. Returned type is ignored in class decorator, while in method decorator it's taken into account, so decorated method type is incompatible with original method.
– estus
Nov 11 at 15:32
add a comment |
0
This is currently not possible in TypeScript but you may look at this comment and modify hack described there to your needs (i.e. for method decorator usage).
answered Nov 11 at 10:10
syntagma
12.5k1248104
The situation is different in linked comment. Returned type is ignored in class decorator, while in method decorator it's taken into account, so decorated method type is incompatible with original method.
– estus
Nov 11 at 15:32
add a comment |
0
0
0
This is currently not possible in TypeScript but you may look at this comment and modify hack described there to your needs (i.e. for method decorator usage).
answered Nov 11 at 10:10
syntagma
12.5k1248104
This is currently not possible in TypeScript but you may look at this comment and modify hack described there to your needs (i.e. for method decorator usage).
answered Nov 11 at 10:10
syntagma
12.5k1248104
answered Nov 11 at 10:10
syntagma
12.5k1248104
answered Nov 11 at 10:10
syntagma
12.5k1248104
answered Nov 11 at 10:10
syntagma
12.5k1248104
12.5k1248104
The situation is different in linked comment. Returned type is ignored in class decorator, while in method decorator it's taken into account, so decorated method type is incompatible with original method.
– estus
Nov 11 at 15:32
add a comment |
The situation is different in linked comment. Returned type is ignored in class decorator, while in method decorator it's taken into account, so decorated method type is incompatible with original method.
– estus
Nov 11 at 15:32
The situation is different in linked comment. Returned type is ignored in class decorator, while in method decorator it's taken into account, so decorated method type is incompatible with original method.
– estus
Nov 11 at 15:32
The situation is different in linked comment. Returned type is ignored in class decorator, while in method decorator it's taken into account, so decorated method type is incompatible with original method.
– estus
Nov 11 at 15:32
add a comment |
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