typescript笔记

• Partial

type Partial<T> = {
  [P in keyof T]?: T[P];
};

• Required

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

• Readonly

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

• Record

type Record<K extends keyof any, T> = {
    [P in K]: T;
};

• Pick

type Pick<T, K extends keyof T> = {
  [P in K]: T[P];
};

• Exclude

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

type Omit<T,K> = Pick<T,Exclude<keyof T, K>>

• Extract

Type Extract<T, U> = T extends U ? T : never;

• NonNullable

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

• Parameters

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

• Mutable

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