index.ts

import {
  If,
  Not,
  And,
  Or
} from 'typescript-logic'

export type Extends<A, B> = Or<
  Any<B>,
  If<Any<A>,
    Any<B>,
    prv.Extends<A, B>
  >
>

export type Compare<A, B, Options extends Compare.Options = Compare.Options.Default> =
  If<Extends<A, B>,
    If<Extends<B, A>,
      Options['equal' | 'broaderRight' | 'broaderLeft'],
      Options['broaderRight']
    >,
    If<Extends<B, A>,
      Options['broaderLeft'],
      Options['mismatch']
    >
  >

export namespace Compare {
  export type Strict<A, B, Options extends Compare.Options = Compare.Options.Default> =
    If<Extends<A, B>,
      If<Extends<B, A>,
        Options['equal'],
        Options['broaderRight']
      >,
      If<Extends<B, A>,
        Options['broaderLeft'],
        Options['mismatch']
      >
    >

  export interface Options {
    broaderLeft: any
    broaderRight: any
    equal: any,
    mismatch: any
  }

  export namespace Options {
    export interface Default extends Compare.Options {
      broaderLeft: 'broaderLeft'
      broaderRight: 'broaderRight'
      equal: 'equal',
      mismatch: 'mismatch'
    }
  }
}

export type Equal<A, B> = Or<
  And<Any<A>, Any<B>>,
  And<
    And<NotAny<A>, NotAny<B>>,
    And<Extends<A, B>, Extends<B, A>>
  >
>

export type NotEqual<A, B> = Not<Equal<A, B>>

export type Any<Type> = And<
  prv.Extends<Type, 0>,
  prv.Extends<Type, 1>
>

export type NotAny<Type> = Not<Any<Type>>

namespace prv {
  export type Extends<A, B> = [A] extends [B] ? true : false
}