fix(types): fix function prop type inference #11223
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@ktsn this might be up your alley! |
| @@ -154,6 +154,45 @@ const FunctionalScopedSlotsComponent = Vue.extend({ | |||
| } | |||
| }); | |||
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| declare function assertBoolean<A>(value: string extends A ? never : (A extends boolean ? A : never)): true; | |||
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To explain a little: calling assertBoolean(value) will only compile if value is precisely boolean, and not if value is boolean | AnotherType, nor if value is any (the latter is why ...lue: string extends A ? nev... is there—it's just a way to throw if value is any).
| this.functionProp(); // callable (good) | ||
| assertBoolean(this.functionPropWithBooleanReturnType()) |
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For reference...
Before the change, these lines were failing with:
this.functionProp();(property)
functionProp:boolean | Function
This expression is not callable.
No constituent of type 'boolean | Function' is callable. ts(2349)
assertBoolean(this.functionPropWithBooleanReturnType());(property)
functionPropWithBooleanReturnType:boolean | (() => boolean)
This expression is not callable.
Not all constituents of type 'boolean | (() => boolean)' are callable.
Type 'false' has no call signatures. ts(2349)
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Also related: microsoft/TypeScript#17574 and #9873 |
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Note: If it helps with confidence, I've tested that this change works & compiles in a project with 154 different |
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I've been looking for a solution for some time now, thanks! |
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Can anyone look at this? I'd really appreciate it! |
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Hi, is there any update on this? I'd be happy this PR was merged. |
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Can someone look at this? It's been a thorn in our side for a long time. |
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@ktsn ? |
close #9357
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