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Lab, TypeScript Mapped Types with Tuples
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| interface HasGetValue<TValue> { | |
| getValue: () => TValue | |
| } | |
| function transformArray< | |
| TInputs extends Array<HasGetValue<unknown>>, | |
| TOuptuts = { [X in keyof TInputs]: ReturnType<TInputs[X]['getValue']> } | |
| >( | |
| inputs: TInputs | |
| ): TOuptuts { | |
| } | |
| function transformReadonlyArray< | |
| TInputs extends ReadonlyArray<HasGetValue<unknown>>, | |
| TOuptuts = { [X in keyof TInputs]: ReturnType<TInputs[X]['getValue']> } | |
| >( | |
| inputs: TInputs | |
| ): TOuptuts { | |
| } | |
| function transformConstReadonlyArray< | |
| const TInputs extends ReadonlyArray<HasGetValue<unknown>>, | |
| TOuptuts = { [X in keyof TInputs]: ReturnType<TInputs[X]['getValue']> } | |
| >( | |
| inputs: TInputs | |
| ): TOuptuts { | |
| } | |
| function transformReadonlyArrayUsingVariadic< | |
| TValues extends ReadonlyArray<HasGetValue<unknown>>, | |
| TValuesAsTuple extends [...TValues], | |
| TOuptuts = { [X in keyof TValuesAsTuple]: ReturnType<TValuesAsTuple[X]['getValue']> } | |
| >( | |
| inputs: TValues | |
| ): TOuptuts { | |
| } | |
| function transformConstReadonlyArrayUsingVariadic< | |
| const TValues extends ReadonlyArray<HasGetValue<unknown>>, | |
| TValuesAsTuple extends [...TValues], | |
| TOuptuts = { [X in keyof TValuesAsTuple]: ReturnType<TValuesAsTuple[X]['getValue']> } | |
| >( | |
| inputs: TValues | |
| ): TOuptuts { | |
| } | |
| const inputArray = [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] | |
| const inputArrayAsConst = [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] as const | |
| const inputTuple: [HasGetValue<boolean>, HasGetValue<number>] = [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] | |
| { | |
| // (number | boolean)[] | |
| // incorrect | |
| const a = transformArray( | |
| inputArray | |
| ) | |
| // error | |
| const c = transformArray( | |
| inputArrayAsConst | |
| ) | |
| // [boolean, | number] | |
| // correct | |
| const b = transformArray( | |
| inputTuple | |
| ) | |
| // (number | boolean)[] | |
| // incorrect | |
| const d = transformArray( | |
| [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] | |
| ) | |
| } | |
| { | |
| // (number | boolean)[] | |
| // incorrect | |
| const a = transformReadonlyArray( | |
| inputArray | |
| ) | |
| // readonly [boolean, number] | |
| // correct | |
| const c = transformReadonlyArray( | |
| inputArrayAsConst | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const b = transformReadonlyArray( | |
| inputTuple | |
| ) | |
| // (number | boolean)[] | |
| // incorrect | |
| const d = transformReadonlyArray( | |
| [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const e = transformReadonlyArray( | |
| [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] as const | |
| ) | |
| } | |
| { | |
| // (number | boolean)[] | |
| // incorrect | |
| const a = transformConstReadonlyArray( | |
| inputArray | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const c = transformConstReadonlyArray( | |
| inputArrayAsConst | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const b = transformConstReadonlyArray( | |
| inputTuple | |
| ) | |
| // reaadonly [boolean, number] | |
| // correct | |
| const d = transformConstReadonlyArray( | |
| [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] | |
| ) | |
| } | |
| { | |
| // (number | boolean)[] | |
| // incorrect | |
| const a = transformReadonlyArrayUsingVariadic( | |
| inputArray | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const b = transformReadonlyArrayUsingVariadic( | |
| inputArrayAsConst | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const c = transformReadonlyArrayUsingVariadic( | |
| inputTuple | |
| ) | |
| // (number | boolean)[] | |
| // incorrect | |
| const d = transformReadonlyArrayUsingVariadic( | |
| [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const e = transformReadonlyArrayUsingVariadic( | |
| [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] as const | |
| ) | |
| } | |
| { | |
| // (number | boolean)[] | |
| // incorrect | |
| const a = transformConstReadonlyArrayUsingVariadic( | |
| inputArray | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const b = transformConstReadonlyArrayUsingVariadic( | |
| inputArrayAsConst | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const c = transformConstReadonlyArrayUsingVariadic( | |
| inputTuple | |
| ) | |
| // (number | boolean)[] | |
| // correct | |
| const d = transformConstReadonlyArrayUsingVariadic( | |
| [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] | |
| ) | |
| // [boolean, number] | |
| // correct | |
| const e = transformConstReadonlyArrayUsingVariadic( | |
| [ | |
| { | |
| getValue: () => true | |
| }, | |
| { | |
| getValue: () => 1 | |
| }, | |
| ] as const | |
| ) | |
| } |
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