@blueprintjs/icons/src/type-utils/includes.ts

Components, fonts, icons, and css files for creating and displaying icons.

/**
Returns a boolean for whether given two types are equal.

@link https://github.com/microsoft/TypeScript/issues/27024#issuecomment-421529650
*/
type IsEqual<T, U> = (<G>() => G extends T ? 1 : 2) extends <G>() => G extends U ? 1 : 2 ? true : false;

/**
Returns a boolean for whether the given array includes the given item.

This can be useful if another type wants to make a decision based on whether the array includes that item.

@example
```
import {Includes} from 'type-fest';

type hasRed<array extends any[]> = Includes<array, 'red'>;
```

@category Utilities
*/
export type Includes<Value extends any[], Item> =
    IsEqual<Value[0], Item> extends true
        ? true
        : Value extends [Value[0], ...infer rest]
          ? Includes<rest, Item>
          : false;