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

我尝试创建一个通用的复制/克隆服务,为嵌套对象保留类型。会爱反馈,如果我做错了什么,但它似乎工作到目前为止…

import { Injectable } from '@angular/core';

@Injectable()
export class CopyService {

  public deepCopy<T>(objectToClone: T): T {
    // If it's a simple type or null, just return it.
    if (typeof objectToClone === 'string' ||
      typeof objectToClone === 'number' ||
      typeof objectToClone === 'undefined' ||
      typeof objectToClone === 'symbol' ||
      typeof objectToClone === 'function' ||
      typeof objectToClone === 'boolean' ||
      objectToClone === null
    ) {
      return objectToClone;
    }

    // Otherwise, check if it has a constructor we can use to properly instantiate it...
    let ctor = Object.getPrototypeOf(objectToClone).constructor;
    if (ctor) {
      let clone = new ctor();

      // Once we've instantiated the correct type, assign the child properties with deep copies of the values
      Object.keys(objectToClone).forEach(key => {
        if (Array.isArray(objectToClone[key]))
          clone[key] = objectToClone[key].map(item => this.deepCopy(item));
        else
          clone[key] = this.deepCopy(objectToClone[key]);
      });

      if (JSON.stringify(objectToClone) !== JSON.stringify(clone))
        console.warn('object cloned, but doesnt match exactly...\nobject: ' + JSON.stringify(objectToClone) + "\nclone: " + JSON.stringify(clone))

      // return our cloned object...
      return clone;
    }
    else {
      //not sure this will ever get hit, but figured I'd have a catch call.
      console.log('deep copy found something it didnt know: ' + JSON.stringify(objectToClone));
      return objectToClone;
    }
  }
}

其他回答

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;
  }

TypeScript/JavaScript有自己的浅克隆操作符:

let shallowClone = { ...original };

你可以在扩展语法中使用解构赋值:

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

这是我的混搭!这里有一个StackBlitz的链接。它目前仅限于复制简单的类型和对象类型,但我认为可以很容易地修改。

   let deepClone = <T>(source: T): { [k: string]: any } => {
      let results: { [k: string]: any } = {};
      for (let P in source) {
        if (typeof source[P] === 'object') {
          results[P] = deepClone(source[P]);
        } else {
          results[P] = source[P];
        }
      }
      return results;
    };

如果还想复制方法,而不仅仅是复制数据,请遵循此方法

let copy = new BaseLayer() ;
Object.assign(copy, origin);
copy.x = 8 ; //will not affect the origin object

只需将BaseLayer更改为类的名称。