Exclude<T, U>

type Exclude<T, U> = T extends U ? never : T

type numberOnly = Exclude<string | number, string>
const a: numberOnly = 5
// const a: number

Exclude<string | number, number>
    => Exclude<string, number> | Exclude<number, number>
    => string | never =>
    => string

interface Student {
  name: string
  age: number
  address: string
  gpa: number
}

type refiendStudent = Exclude<keyof Student, 'address'>
//type refiendStudent = "name" | "age" | "gpa"

type neverType = Exclude<string, string>
// type neverType = never