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expect type helper
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| /* | |
| From TypeStrong/ts-expect | |
| MIT License | |
| https://github.com/TypeStrong/ts-expect/blob/master/src/index.ts | |
| */ | |
| /** | |
| * Checks that `Subtype` is assignable to `Type`. | |
| * | |
| * ```ts | |
| * assertType<TypeOf<number, 123>>(true) | |
| * assertType<TypeOf<123, number>>(false) | |
| * ``` | |
| */ | |
| export type TypeOf<Type, Subtype> = | |
| Exclude<Subtype, Type> extends never ? true : false | |
| /** | |
| * Checks that `A` is equal to the same type as `B`. | |
| * | |
| * ```ts | |
| * assertType<TypeEqual<123, 123>>(true) | |
| * assertType<TypeEqual<123, number>>(false) | |
| * assertType<TypeEqual<number, 123>>(false) | |
| * assertType<TypeEqual<number, number>>(true) | |
| * ``` | |
| */ | |
| export type TypeEqual<A, B> = ( | |
| <T>() => T extends A ? 1 : 2 | |
| ) extends ( | |
| <T>() => T extends B ? 1 : 2 | |
| ) ? true : false | |
| /** | |
| * Asserts the `value` type is assignable to the generic `Type`. | |
| * | |
| * ```ts | |
| * assertType<number>(123) | |
| * assertType<boolean>(true) | |
| * ``` | |
| */ | |
| export const assertType = <Type>(_: Type): void => void 0 |
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