// 通过接口(interface) 声明对象类型interfaceInfoType{readonlyname:string// 只读属性age?:number// 可选属性height:number}// 指定对象的类型constinfo:InfoType= {name:'zhangsan',age:20,height:170}console.log(info.name);// info.name = 'lisi'; // 只读属性不能修改info.age=22;// 可以修改 如上...
// 抛出异常的函数永远不会有返回值functionerror(message:string):never{thrownewError(message);}// 空数组,而且永远是空的constempty:never[]=[] 数组。用法示例: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 constlist:Array<number>=[1,2,3]constlist:number[]=[1,2,3] 元组。表示一个已知元...
//Type 'string' is not assignable to type 'number'. --strictPropertyInitialization strictPropertyInitialization设置控制类字段是否需要在构造函数中初始化。 class BadGreeter { name: string; //Property 'name' has no initializer and is not definitely assigned in the constructor. } class GoodGreeter { ...
type MapAwaited<TArray> ={ [Indexinkeyof TArray] : Awaited<TArray[Index]>}; declarefunctionPromiseAll<T extends readonly unknown[]>(values: readonly [...T]): Promise<MapAwaited<T>>; 它的作用有点类型 infer values 里面的类型, 变成 Tuple. 注意是 Tuple 而不是 Array 哦. 5. Template L...
TypeScript中indexable Types 形如interface StringArray { [index:number]: string }, 可以理解为该接口indexable。 TypeScript中symbol是primitive data type.和number, string一样,symbol是immutable, unique. Symbol.iterator 即为常用的symbol,用来实现迭代器. 搭配for ... of语法 async方法可以包含await表达式...
declare是ts中用于写定义文件的关键字。 declare可以定义全局变量,全局函数,全局命名空间,class等等。 declare可以按照下面这样去使用: declare var foo:number;declare function greet(greeting: string): void;declare namespace myLib {function makeGreeting(s: string): string;let numberOfGreeting: number;}declare...
let sentence: string = `Hello, my name is ${ name }. // 数组,第二种方式是使用数组泛型,Array: let list: number[] = [1, 2, 3]; let list: Array = [1, 2, 3]; let u: undefined = undefined; let n: null = null; 1. ...
declare module "*.vue" { import Vue from "vue"; export default Vue; } 1. 2. 3. 4. 5. 四、文件改造 将src 目录下的所有 js 文件后缀改为 .ts 然后将 webpack 配置文件 ./build/webpack.base.conf.js 中的入口 entry 修改为 main.ts ...
// Type definitions for Kendo UI declare module kendo { function bind(selector: string, viewModel: any, namespace?: any): void; function bind(element: JQuery, viewModel: any, namespace?: any): void; function bind(element: Element, viewModel: any, namespace?: any): void; function culture...
declare function f<T>(x?: T): T; let [x, y, z] = f(); The binding pattern [x, y, z] hinted that f should produce an [any, any, any] tuple; but f really shouldn’t change its type argument based on a binding pattern. It can’t suddenly conjure up a new array-like ...