1.通过TS检测的万金油let a as unknown as any//嵌套函数 即函数内命名函数及调用,TS检测不到const fn: (a: string[], cb: () => void ) => nerver = function(){ const annoy = function(){};// annoy就会逃脱TS的类型检测,因为TS属于结构类 typescript list 连接 Typescript 类型检查 联合标识 T...
private _name: string = '福特'; private _time: string = '2021-12-23'; get name() { return this._name } set name(value: string) { this._name = value } get time(){ return this._time } set time(value:string){ this._time=value } } let car = new Car(); console.log(); c...
//filter let arr38_contains_l = arr38.filter((value: string, index: number, array: string[]) => { return value.indexOf("l") > 0 }) console.log("filter示例:数组中包含l的元素是", arr38_contains_l) //forEach arr38.forEach((value: string, index: number, array: string[]) =>...
interface ReactNodeArray extends Array<ReactNode>{} type ReactFragment= {} |ReactNodeArray; type ReactNode= ReactChild | ReactFragment | ReactPortal |boolean|null| undefined; 可以看到,ReactNode是一个联合类型,它可以是string、number、ReactElement、null、boolean、ReactNodeArray。由此可知。ReactElement类...
a defined callback function on each element of an array, and returns an array that contains the...
*/call(num:string):void/** * 发短信 */sendMessage(num:string,message:string):void}// 表示 DI.IPhone 这个标识符关联的就是 IPhone 接口类型declare global{interfaceDIMapper{'DI.IPhone':IPhone}} 我们稍微改造一下依赖注入相关方法的实现:
: boolean;/*** The warning message*/message: string;} 1.2.6@eventProperty 当应用于类或接口属性时,这表示该属性 返回事件处理程序可以附加到的事件对象。事件处理 API 是实现定义的,但通常属性返回类型是一个类 与成员如addHandler()和removeHandler()。文档工具可以 在“Events”标题下显示此类属性,而不是...
1. Input is correctly refined to be one of the strings in the haystack array declare let s: number | string if ((['foo', 'bar'] as const).includes(s)) { // s is 'foo' | 'bar' here if (s === 'baz') {} // Error as expected, since this is would always be false } ...
// 在元素类型后面加上[] let arr: number[] = [1, 2]; // 或者使用数组泛型 let arr: Array<number> = [1, 2]; 元组 无 元组类型用来表示已知元素数量和类型的数组,各元素的类型不必相同,对应位置的类型需要相同。let x: [string, number]; x = ['hello', 1]; // 运行正常 x = [1, '...
function f(x: unknown) { switch (true) { case typeof x === "string": // 'x' is a 'string' here console.log(x.toUpperCase()); // falls through... case Array.isArray(x): // 'x' is a 'string | any[]' here. console.log(x.length); // falls through... default: // ...