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Type Alias: If<Value, TrueResult, FalseResult>

If<Value, TrueResult, FalseResult> = Value extends true ? TrueResult : Value extends false ? FalseResult : TrueResult | FalseResult

Defined in: types.ts:258

A type utility that allows branching of types depending on the Value parameter.

Type Parameters​

Type Parameter
Value extends boolean
TrueResult
FalseResult

Example​

declare function get<const GetValues extends boolean = false>(
  getValues?: GetValues
): If<GetValues, string, string[]>;

const a = get(true);
//    ^? string

const b = get(false);
//    ^? string[]

declare const someBoolean: boolean;
const c = get(someBoolean);
//    ^? string | string[]