在 TypeScript 中，我们只需要在函数的第一个参数中声明 this 指代的对象（即函数被调用的方式）即可，比如最简单的作为对象的方法的 this 指向，如下代码所示：function say(this: Window, name: string) {console.log(this.name);}window.say = say;window.say('hi');const obj = {say};obj.say('hi')...
Optional Properties适用于"option bags"的设计模式,这种设计模式意思是:我们传递一个对象到函数,这个函数只有几个属性,没有其他更多的属性。 Optional Property的好处在于,清晰的看清楚有哪些属性,防止传入不属于该interface的属性。 interface SquareConfig {color?: string;width?: number;}function createSquare(config:...
<script lang="ts"> import { Component, Prop, Vue } from "vue-property-decorator"; @Component export default class Hello extends Vue { @Prop({ required: true }) private msg!: string; featrues = ['类型注释', 'balabala']; addFeatrue(e:any){ this.featrues.push(e.target.value); e...
typenameProperty=Uncapitalize<'Name'>;// type nameProperty = 'name';typeupercaseDigit=Uppercase<10>;// ❌ 类型“number”不满足约束“string”。typeproperty='phone';typeUppercaseProperty=Uppercase<property>;// type UppercaseProperty = 'Property'; 1. 2. 3. 4. 5. 6. 7. 下面来看一个更复...
比如我们想要实现下面的效果,但是会报错Property 'INITIAL_DATA' does not exist <script> window.__INITIAL_DATA__ = { "userID": "536891193569405430" }; </script> const initialData = window.__INITIAL_DATA__; // 报错 使用类型断言 const initialData = (window as any).__INITIAL_DATA__; typ...
import "reflect-metadata"; export const SerializeMetaKey = "Serialize"; //序列化装饰器 export function Serialize(name?: string) { return (target: Object, property: string): void => { Reflect.defineMetadata(SerializeMetaKey, name || property, target, property); }; } 代码似乎什么都没干,就...
rewindWindowLength: "PT30M", // sets the time-shit(DVR) window to 30 minutes. Uses ISO 8601 format string. hls: { fragmentsPerTsSegment: 1 // Advanced setting when using HLS TS output only. }, } // Create and await the live output await mediaServicesClient.liveOutputs.beginCreate...
可以看到默认 baseURL 为 window.location.host 类似http://localhost:1234/undefined 这种URL 请求成功的情况是存在的。当前端动态传递 url 参数时,参数是有可能为 null 或undefined ,如果不是通过 response 的状态码来响应操作,此时得到的结果就跟预想的不一样。这让我想起了,JavaScript 隐式转换的坑,比比皆是。
arr = ["a", 2]; // error Property '2' is missing in type '[string, number]' but required in type '[string, number, boolean]' arr[1] = 996 1. 2. 3. 4. 5. 可以看到,定义的arr元组中,元素个数和元素类型都是确定的,当为arr赋值时,各个位置上的元素类型都要对应,元素个数也要一致...
Add to your tsconfig.json: "baseUrl": "types", "typeRoots": ["types"], Create types/foo/index.d.ts containing declarations for the module "foo". You should now be able to import from "foo" in your code and it will route to the new type definition. Then build and run the code ...