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
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
试试这个:
let copy = (JSON.parse(JSON.stringify(objectToCopy)));
这是一个很好的解决方案,直到您使用非常大的对象或对象具有不可序列化的属性。
为了保持类型安全,你可以在你想复制的类中使用一个copy函数:
getCopy(): YourClassName{
return (JSON.parse(JSON.stringify(this)));
}
或以静态的方式:
static createCopy(objectToCopy: YourClassName): YourClassName{
return (JSON.parse(JSON.stringify(objectToCopy)));
}
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;
}
}
}