Knowledge Check

User-defined predicate

Which return annotation declares that a function narrows value to Fish when it returns true?

What this task practices

User-defined predicate is a knowledge check interview exercise that trains prompt interpretation, explicit assumptions, a concrete response, and a clear explanation of tradeoffs. The catalog marks it as hard difficulty. It focuses on Frontend Language Browser, Ts Types Narrowing. The signed-in workspace provides the tools for the round and evaluates the attempt against task-specific criteria. Reference solutions, hidden checks, evaluator instructions, and candidate work remain private.