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49 lines
1.1 KiB
TypeScript
49 lines
1.1 KiB
TypeScript
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 a integer, like `-5`, `1.0` or `100`.
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Like [`Number#IsInteger()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/IsInteger) but for types.
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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 intrger or not.
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@example
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```
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type Integer = IsInteger<1>;
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//=> true
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type IntegerWithDecimal = IsInteger<1.0>;
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//=> true
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type NegativeInteger = IsInteger<-1>;
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//=> true
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type Float = IsInteger<1.5>;
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//=> false
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// Supports non-decimal numbers
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type OctalInteger: IsInteger<0o10>;
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//=> true
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type BinaryInteger: IsInteger<0b10>;
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//=> true
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type HexadecimalInteger: IsInteger<0x10>;
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//=> true
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```
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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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