feat: add fallback resolution for indexed access types#1831
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thazhemadam wants to merge 1 commit intolukeautry:masterfrom
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feat: add fallback resolution for indexed access types#1831thazhemadam wants to merge 1 commit intolukeautry:masterfrom
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Indexed access patterns like `T[keyof U], MappedType[Union]`, and `(typeof x)[keyof typeof y]` previously threw "Unknown type: IndexedAccessType". Add a fallback that delegates to TypeScript's type checker to evaluate any indexed access type the compiler accepts, then recursively resolves the resulting simpler type node. In the fallback, ensure that we prevent infinite recursion when `typeToTypeNode` returns another `IndexedAccessTypeNode`, e.g. generic-dependent patterns like `DM[T]`
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Indexed access patterns like
T[keyof U], MappedType[Union], and(typeof x)[keyof typeof y]previously threw"Unknown type: IndexedAccessType".
Add a fallback that delegates to TypeScript's type checker to evaluate any indexed access type the compiler accepts, then recursively resolves the resulting simpler type node.
All Submissions:
Closing issues
Closes #1622.
If this is a new feature submission:
Potential Problems With The Approach
This doesn't fix all forms of the
IndexedAccessTypeNodeerrors.For instance, generic-dependent indexed access types (e.g., as in #1375) are not resolved by this change. In such cases, we bail out to avoid infinite recursion and throw the same error as before.
Test plan
Positive test cases:
ForeignIndexedValue:(typeof x)[keyof typeof y]wherexandyare different objects. Asserts the schema resolves to{ type: "string", enum: ["FOO"] }.EventUnion:{ [K in Union]: ... }[Union], a mapped type indexed by a union alias. Asserts the schema resolves toanyOfwith 2 object variants, each containing the expected properties.ConfigValue:ConfigMap[ConfigKey]whereConfigKey = keyof ConfigMap(GenerateMetadataError: Unknown type: IndexedAccessType #1622 pattern). Asserts the schema resolves to anyOf with 2 variants (the heterogeneous value types of the interface).One negative test case that documents the known limitation:
GenericIndexed<PT.C>:DetailMap[T]whereTis a generic type parameter (GenerateMetadataError: Unknown type: IndexedAccessType #1375 pattern). Asserts that an error is cleanly thrown, rather than stack overflowing.