42 lines
765 B
Plaintext
42 lines
765 B
Plaintext
/**
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Returns a boolean for whether the given number is a float, like `1.5` or `-1.5`.
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Use-case:
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- If you want to make a conditional branch based on the result of whether a number is a float or not.
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@example
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```
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import type {IsFloat, PositiveInfinity} from "type-fest";
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type A = IsFloat<1.5>;
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//=> true
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type B = IsFloat<-1.5>;
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//=> true
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type C = IsFloat<1e-7>;
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//=> true
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type D = IsFloat<1.0>;
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//=> false
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type E = IsFloat<PositiveInfinity>;
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//=> false
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type F = IsFloat<1.23e+21>;
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//=> false
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```
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@category Type Guard
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@category Numeric
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*/
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export type IsFloat<T> = T extends number
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? `${T}` extends `${number}e${infer E extends '-' | '+'}${number}`
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? E extends '-'
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? true
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: false
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: `${T}` extends `${number}.${number}`
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? true
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: false
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: false;
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