extends 繼承
export type Extends<T,U> = T extends U;
複製程式碼readonly 只讀
export type Readonly<T> = { readonly [P in keyof T]: T[P] };
複製程式碼is 是
export type IsType<T> = (val: any) => val is T;
複製程式碼場景：判斷是否屬於某個或某類值
// 是否object
export const isObj: IsType<object>;
// 是否number
export const isNumber: IsType<number>;
// 是否string
export const isString: IsType<string>;
複製程式碼keyof 鍵值
export type KeyOf<T> = keyof T;
複製程式碼利用
K extends keyof WindowEventMap將引數type:K限制在WindowEventMap的鍵值列表，listener中的引數ev限定為WindowEventMap對應K相應的值
declare function addEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
複製程式碼in 在*中
export type Partial<T> = { [P in keyof T]?: T[P] };
複製程式碼? 二義符
export type Extract<T, U> = T extends U ? T : never;
複製程式碼& 合併
export type Merge<T,U> = T & U;
複製程式碼實用
export type IsType<T = any> = (val: any) => val is T;
export type KeyOf<T> = keyof T;
export type Defaultize<P, D> = P extends any
? string extends keyof P
? P
: Pick<P, Exclude<keyof P, keyof D>> &
Partial<Pick<P, Extract<keyof P, keyof D>>> &
Partial<Pick<D, Exclude<keyof D, keyof P>>>
: never;
export type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
export type Matching<InjectedProps, DecorationTargetProps> = {
[P in keyof DecorationTargetProps]: P extends keyof InjectedProps
? InjectedProps[P] extends DecorationTargetProps[P]
? DecorationTargetProps[P]
: InjectedProps[P]
: DecorationTargetProps[P]
};
export type MergePropTypes<P, T> = P & Pick<T, Exclude<keyof T, keyof P>>;
export type Partial<T> = { [P in keyof T]?: T[P] };
export type Required<T> = { [P in keyof T]-?: T[P] };
export type Readonly<T> = { readonly [P in keyof T]: T[P] };
export type Pick<T, K extends keyof T> = { [P in K]: T[P] };
export type Record<K extends keyof any, T> = { [P in K]: T };
export type Exclude<T, U> = T extends U ? never : T;
export type Extract<T, U> = T extends U ? T : never;
export type NonNullable<T> = T extends null | undefined ? never : T;
export type ReturnType<T extends (...args: any[]) => any> = T extends (
...args: any[]
) => infer R
? R
: any;
export type InstanceType<
T extends new (...args: any[]) => any
> = T extends new (...args: any[]) => infer R ? R : any;
複製程式碼