pipe.ts

type PipeCurrying<T> = <F extends ((previousValue: T) => unknown) | undefined>(value?: F) => undefined extends F ? T : PipeCurrying<F extends (value: T) => infer R ? R : unknown>

/**
 * Pipe function
 * @example pipe(123)() // 123
 * @example pipe(123)(v => v + 456)() // 579
 * @example pipe({a: 3})(v => v.a)(v => v * 15)(v => v.toString(16))(v => '0x' + v)() // 0x2d
 */
function pipe<T>(initialValue: T): PipeCurrying<T> {
  return ((value?: (previousValue: T) => unknown) => {
    if (value === void 0) return initialValue
    else return pipe(value(initialValue))
  }) as PipeCurrying<T>
}

const r = pipe(3)(v => v.toString())(v => parseInt(v))(v => v + 2)

console.log(r)