number-comparators.ts

type CompareNumbers<
  T extends number,
  U extends number,
  A extends any[] = [],
> = T extends U
  ? 0 : A['length'] extends T
    ? -1
    : A['length'] extends U
      ? 1
      : CompareNumbers<T, U, ['a', ...A]>

type Not<T> = 
    T extends true ? false : true;

type Equal<L extends number, R extends number> = CompareNumbers<L, R> extends 0 ? true : false;
type LessThan<L extends number, R extends number> = CompareNumbers<L, R> extends -1 ? true : false;
type GreaterThan<L extends number, R extends number> = CompareNumbers<L, R> extends 1 ? true : false;

type Operator = '==' | '!=' | '<' | '>' | '>=' | '<=';

type Conditional<L extends number, O extends Operator, R extends number> = {
    left: L,
    operator: O,
    right: R
}

type Evaluate<C extends Conditional<any, any, any>> = 
    C extends Conditional<infer L, '==', infer R>
    ? Equal<L, R>
    : C extends Conditional<infer L, '!=', infer R>
    ? Not<Equal<L, R>>
    : C extends Conditional<infer L, '<', infer R>
    ? LessThan<L, R>
    : C extends Conditional<infer L, '<=', infer R>
    ? Not<GreaterThan<L, R>>
    : C extends Conditional<infer L, '>', infer R>
    ? GreaterThan<L, R>
    : C extends Conditional<infer L, '>=', infer R>
    ? Not<LessThan<L, R>>
    : unknown;