我们可以在 javascript 中将通用对象转换为自定义对象类型吗？
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Can we cast a generic object to a custom object type in javascript?
提问by bobo
For example, I already have this object somewhere in the code, it is a generic object:
例如，我在代码的某处已经有了这个对象，它是一个通用对象：
var person1={lastName:"Freeman",firstName:"Gordon"};
I have the constructor for a Person object:
我有一个 Person 对象的构造函数：
function Person(){
this.getFullName=function(){
return this.lastName + ' ' + this.firstName;
}
}
Is there a simple syntax that allows us to convert person1 to an object of type Person?
是否有一种简单的语法允许我们将 person1 转换为 Person 类型的对象？
回答by A1rPun
The answer of @PeterOlson may be worked back in the day but it looks like
Object.createis changed. I would go for the copy-constructor way like @user166390 said in the comments.
The reason I necromanced this post is because I needed such implementation.
@PeterOlson 的答案可能会在当天恢复，但看起来
Object.create已经改变了。我会选择像@user166390 在评论中所说的复制构造函数方式。
我死记硬背这篇文章的原因是因为我需要这样的实现。
Nowadays we can use Object.assign(credits to @SayanPal solution) & ES6 syntax:
现在我们可以使用Object.assign（归功于@SayanPal 解决方案）和 ES6 语法：
class Person {
constructor(obj) {
obj && Object.assign(this, obj);
}
getFullName() {
return `${this.lastName} ${this.firstName}`;
}
}
Usage:
用法：
const newPerson = new Person(person1)
newPerson.getFullName() // -> Freeman Gordon
ES5 answer below
ES5答案如下
function Person(obj) {
for(var prop in obj){
// for safety you can use the hasOwnProperty function
this[prop] = obj[prop];
}
}
Usage:
用法：
var newPerson = new Person(person1);
console.log(newPerson.getFullName()); // -> Freeman Gordon
Using a shorter version, 1.5 liner:
使用较短的版本，1.5 衬垫：
function Person(){
if(arguments[0]) for(var prop in arguments[0]) this[prop] = arguments[0][prop];
}
jsfiddle
提琴手
回答by Adam Rackis
No.
不。
But if you're looking to treat your person1object as if it were a Person, you can call methods on Person's prototype on person1with call:
但是，如果你正在寻找把你的person1对象，就好像它是一个Person，你可以调用方法Person上的原型person1有call：
Person.prototype.getFullNamePublic = function(){
return this.lastName + ' ' + this.firstName;
}
Person.prototype.getFullNamePublic.call(person1);
Though this obviously won't work for privileged methods created inside of the Person constructor—like your getFullNamemethod.
尽管这显然不适用于在 Person 构造函数内部创建的特权方法，例如您的getFullName方法。
回答by Sayan Pal
This is not exactly an answer, rather sharing my findings, and hopefully getting some critical argument for/against it, as specifically I am not aware how efficient it is.
这不完全是一个答案，而是分享我的发现，并希望得到一些支持/反对它的批判性论点，因为我不知道它的效率如何。
I recently had a need to do this for my project. I did this using Object.assign, more precisely it is done something like this:Object.assign(new Person(...), anObjectLikePerson).
我最近需要为我的项目执行此操作。我这样做是使用Object.assign，更确切地说是做这样的事情：Object.assign(new Person(...), anObjectLikePerson)。
Here is link to my JSFiddle, and also the main part of the code:
这是我的JSFiddle 的链接，也是代码的主要部分：
function Person(firstName, lastName) {
this.firstName = firstName;
this.lastName = lastName;
this.getFullName = function() {
return this.lastName + ' ' + this.firstName;
}
}
var persons = [{
lastName: "Freeman",
firstName: "Gordon"
}, {
lastName: "Smith",
firstName: "John"
}];
var stronglyTypedPersons = [];
for (var i = 0; i < persons.length; i++) {
stronglyTypedPersons.push(Object.assign(new Person("", ""), persons[i]));
}
回答by pasx
This is just a wrap up of Sayan Pal answer in a shorter form, ES5 style :
这只是以更短的形式，ES5 风格对 Sayan Pal 答案的总结：
var Foo = function(){
this.bar = undefined;
this.buzz = undefined;
}
var foo = Object.assign(new Foo(),{
bar: "whatever",
buzz: "something else"
});
I like it because it is the closest to the very neat object initialisation in .Net:
我喜欢它，因为它最接近 .Net 中非常简洁的对象初始化：
var foo = new Foo()
{
bar: "whatever",
...
回答by Obi
This borrows from a few other answers here but I thought it might help someone. If you define the following function on your custom object, then you have a factory function that you can pass a generic object into and it will return for you an instance of the class.
这借鉴了这里的其他一些答案，但我认为它可能对某人有所帮助。如果您在自定义对象上定义以下函数，那么您就有了一个工厂函数，您可以将一个通用对象传递给它，它会为您返回一个类的实例。
CustomObject.create = function (obj) {
var field = new CustomObject();
for (var prop in obj) {
if (field.hasOwnProperty(prop)) {
field[prop] = obj[prop];
}
}
return field;
}
Use like this
像这样使用
var typedObj = CustomObject.create(genericObj);
回答by Lovro
This worked for me. It's simple for simple objects.
这对我有用。对于简单的对象，这很简单。
class Person {
constructor(firstName, lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
getFullName() {
return this.lastName + " " + this.firstName;
}
static class(obj) {
return new Person(obj.firstName, obj.lastName);
}
}
var person1 = {
lastName: "Freeman",
firstName: "Gordon"
};
var gordon = Person.class(person1);
console.log(gordon.getFullName());I was also searching for a simple solution, and this is what I came up with, based on all other answers and my research. Basically, class Person has another constructor, called 'class' which works with a generic object of the same 'format' as Person. I hope this might help somebody as well.
我也在寻找一个简单的解决方案，这就是我根据所有其他答案和我的研究得出的。基本上，类Person有另一个构造，称为“类”与相同的“格式”作为一个通用的对象的工作人员。我希望这也可以帮助某人。
