59 lines
1.0 KiB
Plaintext
59 lines
1.0 KiB
Plaintext
import type {Not} from './internal';
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import type {IsFloat} from './is-float';
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import type {PositiveInfinity, NegativeInfinity} from './numeric';
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/**
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Returns a boolean for whether the given number is an integer, like `-5`, `1.0`, or `100`.
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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 an integer or not.
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@example
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```
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import type {IsInteger, PositiveInfinity} from "type-fest";
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type A = IsInteger<1>;
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//=> true
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type B = IsInteger<1.0>;
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//=> true
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type C = IsInteger<-1>;
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//=> true
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type D = IsInteger<0b10>;
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//=> true
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type E = IsInteger<0o10>;
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//=> true
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type F = IsInteger<0x10>;
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//=> true
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type G = IsInteger<1.23+21>;
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//=> true
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type H = IsInteger<1.5>;
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//=> false
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type I = IsInteger<PositiveInfinity>;
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//=> false
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type J = IsInteger<1e-7>;
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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 IsInteger<T> =
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T extends bigint
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? true
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: T extends number
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? number extends T
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? false
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: T extends PositiveInfinity | NegativeInfinity
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? false
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: Not<IsFloat<T>>
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: false;
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