我有一个超类,它是许多子类(Customer, Product, ProductCategory…)的父类(Entity)。

我想在Typescript中动态克隆一个包含不同子对象的对象。

例如:拥有不同产品的客户拥有一个ProductCategory

var cust:Customer  = new Customer ();

cust.name = "someName";
cust.products.push(new Product(someId1));
cust.products.push(new Product(someId2));

为了克隆对象的整个树,我在实体中创建了一个函数

public clone():any {
    var cloneObj = new this.constructor();
    for (var attribut in this) {
        if(typeof this[attribut] === "object"){
           cloneObj[attribut] = this.clone();
        } else {
           cloneObj[attribut] = this[attribut];
        }
    }
    return cloneObj;
}

当new被转译为javascript时,将引发以下错误:错误TS2351:不能对缺少调用或构造签名的表达式使用'new'。

虽然脚本工作,但我想摆脱转译错误


当前回答

我在克隆时使用以下方法。它处理我需要的几乎所有东西,甚至将函数复制到新创建的对象。

  public static clone<T>(value: any) : T {
    var o: any = <any>JSON.parse(JSON.stringify(value));
    var functions = (<String[]>Object.getOwnPropertyNames(Object.getPrototypeOf(value))).filter(a => a != 'constructor');
    for (var i = 0; i < functions.length; i++) {
      var name = functions[i].toString();
      o[name] = value[name];
    }
    return <T>o;
  }

其他回答

我自己也遇到过这个问题,最后写了一个小库clone -ts,它提供了一个抽象类,它向任何扩展它的类添加了一个克隆方法。抽象类借用了芬顿接受的答案中描述的深度复制函数,只是替换了Copy = {};使用copy = object. create(originalObj)来保留原始对象的类。下面是一个使用该类的示例。

import {Cloneable, CloneableArgs} from 'cloneable-ts';

// Interface that will be used as named arguments to initialize and clone an object
interface PersonArgs {
    readonly name: string;
    readonly age: number;
}

// Cloneable abstract class initializes the object with super method and adds the clone method
// CloneableArgs interface ensures that all properties defined in the argument interface are defined in class
class Person extends Cloneable<TestArgs>  implements CloneableArgs<PersonArgs> {
    readonly name: string;
    readonly age: number;

    constructor(args: TestArgs) {
        super(args);
    }
}

const a = new Person({name: 'Alice', age: 28});
const b = a.clone({name: 'Bob'})
a.name // Alice
b.name // Bob
b.age // 28

或者你可以直接用克隆。克隆助手方法:

import {Cloneable} from 'cloneable-ts';

interface Person {
    readonly name: string;
    readonly age: number;
}

const a: Person = {name: 'Alice', age: 28};
const b = Cloneable.clone(a, {name: 'Bob'})
a.name // Alice
b.name // Bob
b.age // 28    

下面是deepCopy在TypeScript中的实现(代码中不包含任何内容):

const deepCopy = <T, U = T extends Array<infer V> ? V : never>(source: T ): T => {
  if (Array.isArray(source)) {
    return source.map(item => (deepCopy(item))) as T & U[]
  }
  if (source instanceof Date) {
    return new Date(source.getTime()) as T & Date
  }
  if (source && typeof source === 'object') {
    return (Object.getOwnPropertyNames(source) as (keyof T)[]).reduce<T>((o, prop) => {
      Object.defineProperty(o, prop, Object.getOwnPropertyDescriptor(source, prop)!)
      o[prop] = deepCopy(source[prop])
      return o
    }, Object.create(Object.getPrototypeOf(source)))
  }
  return source
}

在typeScript中,我用angular进行了测试,结果还不错

deepCopy(obj) {


        var copy;

        // Handle the 3 simple types, and null or undefined
        if (null == obj || "object" != typeof obj) return obj;

        // Handle Date
        if (obj instanceof Date) {
            copy = new Date();
            copy.setTime(obj.getTime());
            return copy;
        }

        // Handle Array
        if (obj instanceof Array) {
            copy = [];
            for (var i = 0, len = obj.length; i < len; i++) {
                copy[i] = this.deepCopy(obj[i]);
            }
            return copy;
        }

        // Handle Object
        if (obj instanceof Object) {
            copy = {};
            for (var attr in obj) {
                if (obj.hasOwnProperty(attr)) copy[attr] = this.deepCopy(obj[attr]);
            }
            return copy;
        }

        throw new Error("Unable to copy obj! Its type isn't supported.");
    }

jQuery怎么样?!下面是深度克隆:

var clone = $.extend(true, {}, sourceObject);

你可以在扩展语法中使用解构赋值:

var obj = {id = 1, name = 'product1'};
var clonedObject = {...obj};