Exclude type高级类型-TS内置泛型约束排除

定律：子类 extends 父类 ===》 返回false，返回T类型 语法： type Exclude<T,U> = T extends U ? never : T

interface IWorker {
    name:string
    age:number
    email:string
    salary:number
}
interface IStudent {
    name:string
    age:number
    email:string
    grade:number
}

type exc = Exclude<keyof IWorker,keyof IStudent> //返回 salary