Question

问题：我想通过向其中定义的对象添加其他属性来扩展类。这是场景：

我定义了以下类：

export class SiteProperties {
     properties : {
         name: string;
     }
}

我将此类用作以下类的构建块

export class Site extends SiteProperties {
     parent : SiteProperties[];
     online: number;
     issues: number;
}

问题是我想扩展SiteProperties以在＆＃39;属性中包含其他字段。对象，使它成为：

export class SitePropertiesDetails { 
    properties : {
       name: string,
       description: string    // I basically want to add this field by extending the first SiteProperties class I created
   }
}

有关如何通过某种方式扩展原始name类来避免重复上一个SitePropertiesDetails类内的SiteProperties属性的任何想法？

Answer 1

正如James Monger指出的那样，也许这不是一条路？

如果它是您想要的，那么您可以使用带有可选参数的接口来定义properties对象：

＆＃13;

interface ISiteProperties {
	parent?: SiteProperties[];
	online?: number;
	issues?: number;
	name?: string;
	description?: string;
}

class SiteProperties {
	public properties: ISiteProperties = {};
	constructor() {
		this.properties.name = "Test name";
	}
}

class Site extends SiteProperties {
	constructor() {
		super();
		this.properties.online = 123;
		this.properties.issues = 321;
	}
}


var obj1 = new SiteProperties(), obj2 = new Site();

console.log(obj1);
console.log(obj2);

＆＃13;

和javascript版本：

＆＃13;

var __extends = (this && this.__extends) || function (d, b) {
    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
    function __() { this.constructor = d; }
    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var SiteProperties = (function () {
    function SiteProperties() {
        this.properties = {};
        this.properties.name = "Test name";
    }
    return SiteProperties;
}());
var Site = (function (_super) {
    __extends(Site, _super);
    function Site() {
        _super.call(this);
        this.properties.online = 123;
        this.properties.issues = 321;
    }
    return Site;
}(SiteProperties));
var obj1 = new SiteProperties(), obj2 = new Site();
console.log(obj1);
console.log(obj2);

＆＃13;

Answer 2

我要说最好的OOP方法是在类本身上拥有属性，而不是在匿名对象中。

export class SiteProperties {
    name: string;
}

export class Site extends SiteProperties {
    parent: SiteProperties[];
    online: number;
    issues: number;
}

export class SitePropertiesDetails extends SiteProperties { 
    description: string;
}

let x = new SitePropertiesDetails();
x.name = "Site Number One";
x.description = "The best site there is!";

如您所见，SitePropertiesDetails同时包含name和description。这符合您的需求吗？

如何在类中扩展对象定义？

2 个答案: