typeReadonlyObject<T>={readonly[PinkeyofT]:T[P];};constobj:ReadonlyObject<{name:string;age:number}>={name:"Alice",age:20,};obj.name="Bob";// Error: Cannot assign to 'name' because it is a read-only property. 类型守卫 类型守卫是 TypeScript 中一种用于缩小类型范围的机制。通过使用类...
interface Hero { // Hero 接口 id: number; name: string; } getHeroes(): Observable<Hero[]> { return Observable.of([ { id: 1, name: 'Windstorm' }, { id: 13, name: 'Bombasto' }, { id: 15, name: 'Magneta' }, { id: 20, name: 'Tornado' } ]); } 上面getHeroes(): Obse...
getFullName();//Uncaught TypeError: Cannot destructure property `a` of 'undefined' or 'null'.getFullName({ age: 18, phone: 110 });//'undefined undefined'getFullName({ firstName: "Hello" });//'Hello undefined' 这些都是我们不想要的,在开发时难免会传入错误的参数,所以 TypeScript 能够在编...
exportclassPerson{ firstName: string; lastName: string;constructor(fn: string, ln: string) {this.firstName = fn;this.lastName = ln; } greet() : string {returnthis.fullName +" says hello!"; }getfullName() : string {returnthis.firstName +" "+this.lastNam...
functiongetUrls(url: string | URL, names: string[]){if(typeofurl==="string") {url=newURL(url); }returnnames.map(name => {url.searchParams.set("name", name)// ~~~// error!// Property 'searchParams' does not exist on type 'string | URL'.returnurl.toString(); }); } Here,...
type KeyOfType = typeof strA; // string // 反推出对象的类型作为新的类型 let person = { name: '张三', getName(name: string):void { console.log(name); } } type Person = typeof person; 1. 2. 3. 4. 5. 6. 7. 8. 9. ...
#name: string; constructor(name: string) { this.#name = name; } greet() { console.log(`Hello, my name is ${this.#name}!`); } } let semlinker = new Person("Semlinker"); semlinker.#name; // ~~~ // Property '#name' is not accessible outside class 'Person' //...
{path:'/about/index',name:'AboutIndex',// 检查name是否一致component:()=>import('@/views/about/index.vue') } 项目规范 .vue 文件行数规范 一般来说,一个 .vue 文件行数建议不超过400行,超过建议组件化拆分 变量命名 <script setup lang="ts"> ...
error(getNameOfDeclaration(source.declarations[0]), Diagnostics.Cannot_augment_module_0_with_value_exports_because_it_resolves_to_a_non_module_entity, symbolToString(target)); } else { const message = target.flags & SymbolFlags.BlockScopedVariable || source.flags & SymbolFlags.BlockScopedVariable...
(Button:constructor) | the class constructor}** Sometimes a name has special characters that are not a legal TypeScript identifier:** {@link restProtocol.IServerResponse."first-name" | the first name property}** Here is a fairly elaborate example where the function name is an ECMAScript 6...