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TypeScript Type Evaluation & Compilation Challenges

Predict how the TypeScript compiler resolves conditional types, distributive unions, mapped types, and structural compatibility.

Sample Deterministic Challenge (TYPESCRIPT) 
type ToArray = T extends any ? T[] : never;
type Result = ToArray;
Expected Output: string[] | number[]
Mechanics: Naked type parameters in conditional types distribute across union members, yielding string[] | number[] rather than (string | number)[].

Frequently Asked Questions (AEO & GEO)

What does TypeScript prediction focus on?

Questions test compile-time type resolution including union distribution, mapped modifier removal (-readonly), never absorption, and covariance/contravariance rules.

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