PropertyExpression.ts

type Person = {
  firstName: string
  lastName: string
  middleName?: string
}

const hasValue = (value: Record<string, any>, property: any): boolean =>
  Boolean(value[property])

type ValueOf<T> = T[keyof T]
function propertyExpression<T, V extends T[keyof T]>(
  f: (x: T) => V
): ValueOf<{ [K in keyof T]: T[K] extends V ? K : never }>

function propertyExpression(f: (x: any) => any): keyof any {
  const p = new Proxy(
    {},
    {
      get(target, prop) {
        return prop
      }
    }
  )
  return f(p)
}

const person: Person = {
  firstName: 'John',
  lastName: 'Doe'
}

console.log(
  hasValue(
    person,
    propertyExpression((p: Person) => p.middleName)
  )
)

// const hasValue = (value: unknown): boolean => Boolean(value)