1) #define宏定义有一个特别的长处:可以使用 #ifdef ,#ifndef等来进行逻辑判断,还可以使用#undef来取消定义。 2) typedef也有一个特别的长处:它符合范围规则,使用typedef定义的变量类型其作用范围限制在所定义的函数或者文件内(取决于此变量定义的位置),而宏定义则没有这种特性。 4、别人总结的用途: 用途一: 定...
In typescript, the keyof operator works similarly to object.keys method in javascript where it returns the array of object enumerable properties which are mostly in string format so it is possible that it can accept only key arguments which may throw an error at runtime and therefore this is ...
Object:proto、defineGetter、defineSetter、 lookupGetter、lookupSetter、assign、create、 defineProperties、defineProperty、freeze、 fromEntries、getOwnPropertyDescriptor、getOwnPropertyDescriptors、 getOwnPropertySymbols、getPrototypeOf、 hasOwnProperty、is、isExtensible、isFrozen、 isPrototypeOf、isSealed、preventExtensions、 ...
1) Type alias: We can use ‘type’ alias to define or declare our object in TypeScript, they are another type of object in TypeScript. Let’s see its syntax and how to use and create in TypeScript; syntax: type Object_name = { // variables goes here .. }; As you can see in ...
1 2 3 npminstalltypescript -g tsc init ②tsconfig.json文件的作用是typescript对应的编译配置文件 ③运行tsc demo.ts会编译成demo.js文件 ④只有单独输入tsc命令,后面不跟任何参数时,才会执行tsconfig里面的配置 ts-node demo.ts也会执行tsconfig里面的配置项 ...
import"reflect-metadata";constformat:(formatter:string)=>PropertyDecorator=(formatter)=>{return(target:Object,propertyKey:string|symbol)=>{Reflect.defineMetadata(propertyKey,formatter,target)}}classGreeter{@format("Hello, %s")greeting:string;constructor(message:string){this.greeting=message;}greet(){let...
key1: string; key2: string; key3: string; }; 第一个参数是放入所有的属性 keys, 它用一个集合来表示, 也就是Union+String Literal 第二个参数是属性的 value, 也就是类型 (记住, TS 都是在处理类型, 我重复很多次了) Record 函数最终会返回 Object Literal 类型, 它拥有所有的 keys 属性, 每一个...
( defineProps<{ columns: { key: string; label: string; type: 'slot' | 'input' | 'select' }[] }>(), { columns: () => [], }, ) const slots = defineSlots<{ header(props: { disabled: boolean; loading: boolean; submit: (e: MouseEvent) => void }): void...
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...
export const EditorMetaKey = "Editor"; //序列化装饰器 export function Serialize(name?: string) { return (target: Object, property: string): void => { Reflect.defineMetadata(SerializeMetaKey, name || property, target, property); };