add type guard of constructor #23622
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what should i do with |
I'd filter down to the primitive types (e.g. So declare let x: number | true | "hello" | "world;
if (x.constructor === String) {
// x has type `"hello" | "world"` here.
} |
src/compiler/checker.ts
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| const targetType = !isTypeAny(prototypePropertyType) ? prototypePropertyType : undefined; | ||
| if (!targetType || isTypeAny(type) && (targetType === globalObjectType || targetType === globalFunctionType)) return type; | ||
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| return getNarrowedType(type, targetType, assumeTrue, areTypesComparable); |
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I don't think you want areTypesComparable because this will work for types which don't explicitly derive from a given constructor.
I think you potentially want a helper function that uses isTypeDerivedFrom on the wrapper object type for any primitive types.
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will work for types which don't explicitly derive from a given constructor
could you give some example? 😢
src/compiler/utilities.ts
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| @@ -6335,4 +6335,9 @@ namespace ts { | |||
| export function isNamedImportsOrExports(node: Node): node is NamedImportsOrExports { | |||
| return node.kind === SyntaxKind.NamedImports || node.kind === SyntaxKind.NamedExports; | |||
| } | |||
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| /** @internal */ | |||
| export function isExclamationEqualsOrExclamationEqualsEqualsKind(kind: SyntaxKind): boolean { | |||
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Maybe isNegatedEqualityToken? *shrug*
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need take another look😢 |
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Kingwl
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Cycling to get a fresh CI |
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@Kingwl closing for housekeeping; would welcome a fresh PR |
Fixes #23274