fix(typescript): accept union types#9
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callmehiphop wants to merge 1 commit intosindresorhus:masterfrom
callmehiphop:union-types
Closed
fix(typescript): accept union types#9callmehiphop wants to merge 1 commit intosindresorhus:masterfrom callmehiphop:union-types
callmehiphop wants to merge 1 commit intosindresorhus:masterfrom
callmehiphop:union-types
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Owner
BendingBender
suggested changes
Apr 5, 2019
| declare function arrify<ValueType>(value: ValueType[]): ValueType[]; | ||
| declare function arrify<ValueType>(value: Iterable<ValueType>): ValueType[]; | ||
| declare function arrify<ValueType>(value: ValueType): [ValueType]; | ||
| declare function arrify<ValueType>(value: ValueType|ValueType[]): ValueType[]; |
Contributor
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I think that we should rethink the whole definion. What you propose only fixes the case that the parameter is of a special type or an array of this type (number | number[]). What about number | string[] or any other type combination?
I've come up with this one, it seems to work as expected but is very ugly:
Suggested change
| declare function arrify<ValueType>(value: ValueType|ValueType[]): ValueType[]; | |
| declare function arrify<ValueType>( | |
| value: ValueType | |
| ): ValueType extends (null | undefined) | |
| ? [] | |
| : ValueType extends string | |
| ? [string] | |
| : ValueType extends (infer T)[] | |
| ? T[] | |
| : ValueType extends ReadonlyArray<infer T> | |
| ? ReadonlyArray<T> | |
| : ValueType extends Iterable<infer T> | |
| ? T[] | |
| : [ValueType]; |
Do you have a better idea?
Contributor
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: ValueType extends Iterable
? [T]
[T] should be T[]
Contributor
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@callmehiphop Could you please update your PR with the suggested changes?
Author
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I'm ok closing this one out if you want to open a new PR with those changes
Contributor
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Ok, close this one, I'll open a new one.
| arrify(new Map<string | number, string | number>([[1, 2], ['a', 'b']])) | ||
| ); | ||
| expectType<number[]>(arrify(new Set([1, 2]))); | ||
| expectType<number[]>(arrify<number>(Boolean() ? [1, 2] : 3)); |
Contributor
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Following tests pass with just the proposed type above, no other overloads needed:
Suggested change
| expectType<number[]>(arrify<number>(Boolean() ? [1, 2] : 3)); | |
| expectType<[]>(arrify(null)); | |
| expectType<[]>(arrify(undefined)); | |
| expectType<[string]>(arrify('🦄')); | |
| expectType<string[]>(arrify(['🦄'])); | |
| expectType<[boolean]>(arrify(true)); | |
| expectType<[number]>(arrify(1)); | |
| expectType<[{}]>(arrify({})); | |
| expectType<([string | number, string | number])[]>( | |
| arrify(new Map<string | number, string | number>([[1, 2], ['a', 'b']])) | |
| ); | |
| expectType<number[]>(arrify(new Set([1, 2]))); | |
| expectError(arrify(['🦄'] as const).push('')); | |
| expectType<number[] | []>(arrify(Boolean() ? [1, 2] : null)); | |
| expectType<number[] | []>(arrify(Boolean() ? [1, 2] : undefined)); | |
| expectType<number[] | [string]>(arrify(Boolean() ? [1, 2] : '🦄')); | |
| expectType<number[] | string[]>(arrify(Boolean() ? [1, 2] : ['🦄'])); | |
| expectType<number[] | [boolean]>(arrify(Boolean() ? [1, 2] : true)); | |
| expectType<number[] | [number]>(arrify(Boolean() ? [1, 2] : 3)); | |
| expectType<number[] | [{}]>(arrify(Boolean() ? [1, 2] : {})); | |
| expectType<number[] | (string | boolean)[]>( | |
| arrify(Boolean() ? [1, 2] : new Set<string | boolean>(['🦄', true])) | |
| ); | |
| expectType<number[] | [boolean] | [string]>( | |
| arrify(Boolean() ? [1, 2] : Boolean() ? true : '🦄') | |
| ); |
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Fixes #8
Please be gentle!