TS 内置的功能类型 ​

type DPartial<T extends object> = {
    [k in keyof T]?: T[k]
}

type DExclude<T, U> = T extends U ? never : T;

type DOmit<T, U> = DPick<T, DExclude<keyof T, U>>

type DPick<T, U extends keyof T> = {
    [P in U]: T[P] 
}

type DReadonly<T> = {
    readonly [P in keyof T]: T[P]
}

type DRequired<T> = {
    [P in keyof T]-?: T[P]
}

type DNonNullalbe<T> = T extends null | undefined ? never : T

type DExtract<T, U> = T extends U ? never : T;

type DInstanceType<T> = T extends ?

type DReturnType<T> = T extends (...args: any[]) => infer P ? P : never;

type DParameters<T> = T extends (...args: infer P) => any ? P : never;