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Conditional Types

T extends U ? X : Y selects a type by an assignability test, giving the type system branching logic; nesting them builds type-level decision trees. Evaluation is deferred while T contains unresolved type parameters, which is why conditional types compose inside generics.

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T extends U ? X : Y selects a type by an assignability test, giving the type system branching logic; nesting them builds type-level decision trees. Evaluation is deferred while T contains unresolved type parameters, which is why conditional types compose inside generics.

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