Add IsUnion type
#544
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Add IsUnion type
#544
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Permits detecting if a given type is a singular type or a union of types. Useful when you only want to accept a union of types or a single type. This commit uses a pattern where, instead of returning `true` and `false`, the caller can specify the result in the true and false cases. Effectively, you can write: ```ts IsUnion<T, IfTrue, IfFalse> ``` instead of: ```ts IsUnion<T> extends true ? IfTrue : IfFalse ```
sindresorhus
requested changes
Jan 20, 2023
| import type {IsUnion} from 'type-fest'; | ||
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| // If `MaybeSingle` is a union type, resolves to `never`, otherwise MaybeSingle. | ||
| type EnsureSingleType<MaybeSingle> = IsUnion<MaybeSingle, never, MaybeSingle>; |
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I would like a more real-world example.
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Opting to drop this. I do use this in the codebase I work on but I'm fine keeping local there. |
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Permits detecting if a given type is a singular type or a union of types. Useful when you only want to accept a union of types or a single type.
This commit uses a pattern where, instead of returning
trueandfalse, the caller can specify the result in the true and false cases. Effectively, you can write:instead of:
Fixes #236