HarmonyOS鸿蒙Next中Typescript基础语法

HarmonyOS鸿蒙Next中Typescript基础语法

1. 基础类型

   • 布尔值

     let isDone: boolean = true
     

   • 数字

     let a: number = 10
     let b: number = 0b1101
     let c: number = 0o376
     let d: number = 0x73e
     

   • 字符串

     let str: string = 'bac'
     let str1: string = "abc"
     

   • 数组

     使用元素类型后面接[]如：number[]
     使用数组泛型Array<元素类型> 如：Array<number>
     

     let arr: number[] = [1,2,3]
     let arr1: Array<number> = [2,3,4]
     

   • 元组

     let a:[string, number] = ['abc',123]
     

   • 枚举

     enum Color{Red,Green,Blue}
     let a:Color = Color.Red
     

   • unknown

     let a:unknown = 4
     a = 'abc'
     a = [1,2,3]
     

   • void

     function abc():void{}
     

   • null和undefined

     let a:undefined = undefined
     let b:null = null
     

   • 联合类型

     let a:string|number = 'abc'
     a = 10
     

2. 条件语句

   • if…else

     let a:number = 10
     if(a>5){
       ...
     }else if(a>6){
       ...
     }else{
     }
     

   • switch

     let a:string = "A"
     switch(a){
       case "A":{
         ...
         break; 
       }
       case "B":{
         ...
         break; 
       }   
       default:{
         ...
         break;
       }
     }
     

3. 函数

   • 定义

     // 有名函数
     function add(x, y) {
       return x + y;
     }
     
     // 匿名函数
     let myAdd = function (x, y) {
       return x + y;
     };
     

     // 有名函数：给变量设置为number类型
     function add(x: number, y: number): number {
       return x + y;
     }
     
     // 匿名函数：给变量设置为number类型
     let myAdd = function (x: number, y: number): number {
       return x + y;
     };
     

     // 箭头函数
     ( [param1, parma2,…param n] )=> {
       // 代码块
     }
     
     let arrowFun = ([param1, parma2,…param n])=>{
       // 代码块
     }
     arrowFun(param1, parma2,…param n)
     

4. 类

   • 类的定义

     class Person {
       private name: string
       private age: number
     
       constructor(name: string, age: number) {
         this.name = name;
         this.age = age;
       }
     
       public getPersonInfo(): string {
         return `My name is ${this.name} and age is ${this.age}`;
       }
     }
     let person1 = new Person('Jacky', 18);
     person1.getPersonInfo();
     

   • 继承

     class Employee extends Person {
       private department: string
     
       constructor(name: string, age: number, department: string) {
         super(name, age);
         this.department = department;
       }
     
       public getEmployeeInfo(): string {
         return this.getPersonInfo() + ` and work in ${this.department}`;
       }
     }
     
     let person2 = new Employee('Tom', 28, 'HuaWei');
     person2.getPersonInfo();
     person2.getEmployeeInfo();
     

5. 模块

   • 导出

     export class NewsData {
       title: string;
       content: string;
       imagesUrl: Array<NewsFile>;
       source: string;
     
       constructor(title: string, content: string, imagesUrl: Array<NewsFile>, source: string) {
         this.title = title;
         this.content = content;
         this.imagesUrl = imagesUrl;
         this.source = source;
       }
     }
     

   • 导入

     import { NewsData } from '../common/bean/NewsData';
     

6. 迭代器

   • for…of

     let someArray = [1, "string", false];
     
     for (let entry of someArray) {
         console.log(entry); // 1, "string", false
     }
     

   • for…in语句

     let list = [4, 5, 6];
     
     for (let i in list) {
         console.log(i); // "0", "1", "2",
     }
     
     for (let i of list) {
         console.log(i); // "4", "5", "6"
     }