Conditional type

typescript

type IsString<T> = T extends string ? true : false;

Explanation

Conditional types are the basis for many advanced utility helpers.

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Same sheet · prioritizing Mapped and Conditional Types

Use `infer` inside a conditional type.

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Create a type by iterating over keys.

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Model variant objects with a shared discriminant field.

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Use a type parameter for reusable function typing.

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Get a union of property names from a type.

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Make every property optional.

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