008--TypeScript存储器和静态属性
作者：互联网
Typescript支持对一个简单的类进行getter和setter
//ts实现getter和setter
//这个文件只能编译成es5
let passCode = 'Secret Password'
class Employee {
private _fullName: string
get fullName(): string{
return this._fullName
}
set fullName(newName: string) {
if(passCode && passCode == 'Secret Password'){
this._fullName = newName
} else {
console.error ('Error: Unauthorized update of employee!')
}
}
}
let employee = new Employee()
employee.fullName = 'BOb smith'
if (employee.fullName) {
console.log(employee.fullName)//如果passCode正确,输出BOb smith
}
编译后的文件如下
//ts实现getter和setter
//这个文件只能编译成es5
var passCode = 'Secret Password';
var Employee = /** @class */ (function () {
function Employee() {
}
Object.defineProperty(Employee.prototype, "fullName", {
get: function () {
return this._fullName;
},
set: function (newName) {
if (passCode && passCode == 'Secret Password') {
this._fullName = newName;
}
else {
console.error('Error: Unauthorized update of employee!');
}
},
enumerable: true,
configurable: true
});
return Employee;
}());
var employee = new Employee();
employee.fullName = 'BOb smith';
if (employee.fullName) {
console.log(employee.fullName); //如果passCode正确,输出BOb smith
}
创建类的静态成员,这些属性只存在类的本身
//静态属性的使用
//计算坐标系的一点到任一点的距离
class Grid {
static orign = {x:0, y:0}//静态属性,可以直接使用
scale: number //定义缩放比例
constructor(scale: number) {
this.scale = scale//把scale传给this,new函数的时候必须传入
}
//创建一个实例方法
calculateDistanceFromOrign (point: {x:number; y: number}) {
let xDist = point.x - Grid.orign.x //静态属性可以直接使用
let yDist = point.y - Grid.orign.y
//勾股定理
return Math.sqrt(xDist * xDist + yDist * yDist) * this.scale
}
}
let grid1 = new Grid(1.0)
let grid2 = new Grid(5.0)
//勾3股4弦5
console.log(grid1.calculateDistanceFromOrign({x:3 , y:4}))//5
console.log(grid2.calculateDistanceFromOrign({x:3 , y:4}))//25
编译后的文件
//静态属性的使用
//计算坐标系的一点到任一点的距离
var Grid = /** @class */ (function () {
function Grid(scale) {
this.scale = scale; //把scale传给this,new函数的时候必须传入
}
//创建一个实例方法
Grid.prototype.calculateDistanceFromOrign = function (point) {
var xDist = point.x - Grid.orign.x; //静态属性可以直接使用
var yDist = point.y - Grid.orign.y;
//勾股定理
return Math.sqrt(xDist * xDist + yDist * yDist) * this.scale;
};
Grid.orign = { x: 0, y: 0 }; //静态属性,可以直接使用
return Grid;
}());
var grid1 = new Grid(1.0);
var grid2 = new Grid(5.0);
//勾3股4弦5
console.log(grid1.calculateDistanceFromOrign({ x: 3, y: 4 }));
console.log(grid2.calculateDistanceFromOrign({ x: 3, y: 4 }));
TypeScript抽象类
抽象类一般作为其他类的派生类或者基类使用,一般不能直接使用
abstract class Department {
name: string
constructor(name: string) {
this.name = name
}
printName(): void{
console.log('Department name ' + this.name)
}
abstract printMeeting(): void //具体实现要在派生类中实现,这是个签名
}
class AccountingDepartment extends Department {
constructor() {
super('Accounting ad Auditing')
}
//实现抽象方法
printMeeting(): void {
console.log('The Accounting Department meets each monday at 10am')
}
genterateReports(): void {
console.log('Generating accounting reports.. ')
}
}
let department: Department
// department = new Department()//报错,无法创建抽象类的实例
department = new AccountingDepartment()
department.printName()
department.printMeeting()
//department.genterateReports()//定义的是Department类型,没有这个实例方法
//输出
// Department name Accounting ad Auditing
// The Accounting Department meets each monday at 10am
类的一些高级技巧
//类的一些高级技巧
class Greeter {
static standgrdGreeting = 'Hello , there'
greeting: string
constructor(message: string) {
this.greeting = message
}
greet() {
return 'Hello' + this.greeting
}
}
let greeter: Greeter
greeter = new Greeter('world')
console.log(greeter.greet())//Helloworld
可以看到上面的代码有静态属性,有实例方法
//类的一些高级技巧
var Greeter = /** @class */ (function () {
function Greeter(message) {
this.greeting = message;
}
Greeter.prototype.greet = function () {
return 'Hello' + this.greeting;
};
//最开始把构造函数赋值给Greeter变量
//静态属性编译后实际上是挂载在赋值后的Greeter上
Greeter.standgrdGreeting = 'Hello , there';
return Greeter;
}());
var greeter;
greeter = new Greeter('world');
console.log(greeter.greet());
改造后
//类的一些高级技巧
class Greeter {
static standgrdGreeting = 'Hello , there'
greeting: string
//修改为可选参数
constructor(message?: string) {
this.greeting = message
}
greet() {
if(this.greeting){
return 'Hello' + this.greeting
}else {
return Greeter.standgrdGreeting
}
}
}
let greeter: Greeter
greeter = new Greeter()
console.log(greeter.greet())//Hello , there
//如果我们相对standGreeting做修改怎么办呢?
let greetMaker: typeof Greeter = Greeter
greetMaker.standgrdGreeting = 'Hey, htere'
let greeter2:Greeter = new greetMaker()
console.log(greeter2.greet())//Hey, htere
编译后
//类的一些高级技巧
var Greeter = /** @class */ (function () {
//修改为可选参数
function Greeter(message) {
this.greeting = message;
}
Greeter.prototype.greet = function () {
if (this.greeting) {
return 'Hello' + this.greeting;
}
else {
return Greeter.standgrdGreeting;
}
};
Greeter.standgrdGreeting = 'Hello , there';
return Greeter;
}());
var greeter;
greeter = new Greeter();
console.log(greeter.greet()); //Hello , there
//如果我们相对standGreeting做修改怎么办呢?
var greetMaker = Greeter;
greetMaker.standgrdGreeting = 'Hey, htere';
var greeter2 = new greetMaker();
console.log(greeter2.greet());
类作为接口使用
//目前已废弃
class Point {
x: number
y: number
}
interface Point3D extends Point｛
z: number
｝
let point3d: Point3D = {x: 1 ,y: 2, z: 3}
2019-05-27 17:40:40
标签：TypeScript,console,log,存储器,return,Grid,new,Greeter,008 来源： https://www.cnblogs.com/ccbest/p/10932032.html