如果你想要类型安全，不喜欢装饰器

abstract class IPerson{
  name?: string;
  age?: number;
}
class Person extends IPerson{
  constructor({name, age}: IPerson){
    super();
    this.name = name;
    this.age = age;
  }
}

const json = {name: "ali", age: 80};
const person = new Person(json);

或者我更喜欢这个

class Person {
  constructor(init?: Partial<Person>){
      Object.assign(this, init);
  }
  name?: string;
  age?: number;
}

const json = {name: "ali", age: 80};
const person = new Person(json);

你可以像下面这样做

export interface Instance {
  id?:string;
  name?:string;
  type:string;
}

and

var instance: Instance = <Instance>({
      id: null,
      name: '',
      type: ''
    });

选项#5:使用Typescript构造函数和jQuery.extend

这似乎是最可维护的方法:添加一个以json结构作为参数的构造函数，并扩展json对象。这样就可以将json结构解析为整个应用程序模型。

不需要创建接口，或者在构造函数中列出属性。

export class Company
{
    Employees : Employee[];

    constructor( jsonData: any )
    {
        jQuery.extend( this, jsonData);

        // apply the same principle to linked objects:
        if ( jsonData.Employees )
            this.Employees = jQuery.map( jsonData.Employees , (emp) => {
                return new Employee ( emp );  });
    }

    calculateSalaries() : void { .... }
}

export class Employee
{
    name: string;
    salary: number;
    city: string;

    constructor( jsonData: any )
    {
        jQuery.extend( this, jsonData);

        // case where your object's property does not match the json's:
        this.city = jsonData.town;
    }
}

在你的ajax回调中，你收到一个公司来计算工资:

onReceiveCompany( jsonCompany : any ) 
{
   let newCompany = new Company( jsonCompany );

   // call the methods on your newCompany object ...
   newCompany.calculateSalaries()
}

**model.ts**
export class Item {
    private key: JSON;
    constructor(jsonItem: any) {
        this.key = jsonItem;
    }
}

**service.ts**
import { Item } from '../model/items';

export class ItemService {
    items: Item;
    constructor() {
        this.items = new Item({
            'logo': 'Logo',
            'home': 'Home',
            'about': 'About',
            'contact': 'Contact',
        });
    }
    getItems(): Item {
        return this.items;
    }
}

也许不现实，但简单的解决方案:

interface Bar{
x:number;
y?:string; 
}

var baz:Bar = JSON.parse(jsonString);
alert(baz.y);

对困难的依赖也要努力!!

我的方法略有不同。我没有将属性复制到新的实例中，我只是改变了现有pojo的原型(在旧的浏览器上可能不太好用)。每个类负责提供一个setprototype方法来设置任何子对象的原型，这些子对象反过来提供它们自己的setprototype方法。

(我也使用_Type属性来获取未知对象的类名，但在这里可以忽略)

class ParentClass
{
    public ID?: Guid;
    public Child?: ChildClass;
    public ListOfChildren?: ChildClass[];

    /**
     * Set the prototypes of all objects in the graph.
     * Used for recursive prototype assignment on a graph via ObjectUtils.SetPrototypeOf.
     * @param pojo Plain object received from API/JSON to be given the class prototype.
     */
    private static SetPrototypes(pojo: ParentClass): void
    {
        ObjectUtils.SetPrototypeOf(pojo.Child, ChildClass);
        ObjectUtils.SetPrototypeOfAll(pojo.ListOfChildren, ChildClass);
    }
}

class ChildClass
{
    public ID?: Guid;
    public GrandChild?: GrandChildClass;

    /**
     * Set the prototypes of all objects in the graph.
     * Used for recursive prototype assignment on a graph via ObjectUtils.SetPrototypeOf.
     * @param pojo Plain object received from API/JSON to be given the class prototype.
     */
    private static SetPrototypes(pojo: ChildClass): void
    {
        ObjectUtils.SetPrototypeOf(pojo.GrandChild, GrandChildClass);
    }
}

下面是ObjectUtils.ts:

/**
 * ClassType lets us specify arguments as class variables.
 * (where ClassType == window[ClassName])
 */
type ClassType = { new(...args: any[]): any; };

/**
 * The name of a class as opposed to the class itself.
 * (where ClassType == window[ClassName])
 */
type ClassName = string & {};

abstract class ObjectUtils
{
/**
 * Set the prototype of an object to the specified class.
 *
 * Does nothing if source or type are null.
 * Throws an exception if type is not a known class type.
 *
 * If type has the SetPrototypes method then that is called on the source
 * to perform recursive prototype assignment on an object graph.
 *
 * SetPrototypes is declared private on types because it should only be called
 * by this method. It does not (and must not) set the prototype of the object
 * itself - only the protoypes of child properties, otherwise it would cause a
 * loop. Thus a public method would be misleading and not useful on its own.
 * 
 * https://stackoverflow.com/questions/9959727/proto-vs-prototype-in-javascript
 */
public static SetPrototypeOf(source: any, type: ClassType | ClassName): any
{
    let classType = (typeof type === "string") ? window[type] : type;

    if (!source || !classType)
    {
        return source;
    }

    // Guard/contract utility
    ExGuard.IsValid(classType.prototype, "type", <any>type);

    if ((<any>Object).setPrototypeOf)
    {
        (<any>Object).setPrototypeOf(source, classType.prototype);
    }
    else if (source.__proto__)
    {
        source.__proto__ = classType.prototype.__proto__;
    }

    if (typeof classType["SetPrototypes"] === "function")
    {
        classType["SetPrototypes"](source);
    }

    return source;
}

/**
 * Set the prototype of a list of objects to the specified class.
 * 
 * Throws an exception if type is not a known class type.
 */
public static SetPrototypeOfAll(source: any[], type: ClassType): void
{
    if (!source)
    {
        return;
    }

    for (var i = 0; i < source.length; i++)
    {
        this.SetPrototypeOf(source[i], type);
    }
}
}

用法:

let pojo = SomePlainOldJavascriptObjectReceivedViaAjax;

let parentObject = ObjectUtils.SetPrototypeOf(pojo, ParentClass);

// parentObject is now a proper ParentClass instance