复制 Javascript 对象属性

Copying Javascript object attributes

提问by Shawn Mclean

I have 1 object coming from the server with multiple properties in which I want to hydrate it into a new object, changing the name of 1 property and keeping the rest.

我有 1 个来自服务器的对象，它具有多个属性，我想将其合并为一个新对象，更改 1 个属性的名称并保留其余属性。

Code:

代码：

JSON: { UserId: 1, Name: "Woo", Age: 10 }

JSON： { UserId: 1, Name: "Woo", Age: 10 }

The format of the object I want it in:

我想要它的对象的格式：

var newObj = {}
newObj.id = jsonObj.UserId;
//Everything property below here is the same. How can i prevent writing this code?
newObj.Name = jsonObj.Name;
newObj.Age = jsonObj.Age;

What I'm doing is based on this answer, trying to parse some json into a format that requires me to change the name of 1 property.

我正在做的是基于此答案，尝试将一些 json 解析为需要我更改 1 属性名称的格式。

回答by aroth

For such a simple case, you could do something like:

对于这样一个简单的情况，您可以执行以下操作：

var newObj = {id: jsonObj.UserId, Name: jsonObj.Name, Age: jsonObj.Age};

For a more complex object with a large number of fields, you might prefer something like:

对于具有大量字段的更复杂的对象，您可能更喜欢以下内容：

//helper function to clone a given object instance
function copyObject(obj) {
    var newObj = {};
    for (var key in obj) {
        //copy all the fields
        newObj[key] = obj[key];
    }

    return newObj;
}


//now manually make any desired modifications
var newObj = copyObject(jsonObj);
newObj.id = newObj.UserId;

回答by Ronan Quillevere

If you want to copy only specific fields

如果您只想复制特定字段

    /**
    * Returns a new object with only specified fields copied.
    * 
    * @param {Object} original object to copy fields from
    * @param {Array} list of fields names to copy in the new object
    * @return {Object} a new object with only specified fields copied
    */ 
    var copyObjectFields = function (originObject, fieldNamesArray)
    {
        var obj = {};

        if (fieldNamesArray === null)
            return obj;

        for (var i = 0; i < fieldNamesArray.length; i++) {
            obj[fieldNamesArray[i]] = originObject[fieldNamesArray[i]];
        }

        return obj;
    };


//example of method call
var newObj = copyObjectFields (originalObject, ['field1','field2']);

回答by chachan

I mostly prefer to reuse instead of recreate so I'd suggest http://underscorejs.org/#clone

我最喜欢重用而不是重新创建所以我建议http://underscorejs.org/#clone

回答by Benny Tjia

Dont really understand your question, but this is what I normally do when I extract from an existing object:

不太明白您的问题，但这是我从现有对象中提取时通常会做的事情：

var newObj = new Object(jsonObj);
alert(newObj.UserId === jsonObj.UserId); //returns true

Is that what you were asking? Hope that helps.

这就是你问的吗？希望有帮助。

回答by Evgeniy Timchenko

function clone(o) {
 if(!o || 'object' !== typeof o)  {
   return o;
 }
 var c = 'function' === typeof o.pop ? [] : {};
 var p, v;
 for(p in o) {
 if(o.hasOwnProperty(p)) {
  v = o[p];
  if(v && 'object' === typeof v) {
    c[p] = clone(v);
  }
  else {
    c[p] = v;
  }
 }
}
 return c;
}

回答by Tony

Using Object.assign

使用 Object.assign

var newObj = Object.assign({}, jsonObj);

reference (MDN)

参考（MDN）

Using JSON.parse and JSON.stringify;

使用 JSON.parse 和 JSON.stringify；

var newObj = JSON.parse(JSON.stringify(jsonObj));