Javascript 对象引用链接到数组中的对象？
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Javascript object reference linked to object in array?
提问by Rolando
If I have an object:
如果我有一个对象：
var array = [];
var theobject = null;
array.push({song:"The Song", artist:"The Artist"}, {song:"Another Song", artist:"Another Artist"});
and I do:
我这样做：
for(var i = 0; i < array.length; i++)
if(array[i].song == "The Song") {
theobject = array[i];
break;
}
If I then change theobject by doing:
如果我然后通过执行以下操作更改对象：
theobject.song = "Changed Name";
I am having problems where despite myself trying to set ONLY "theobject.song" to be equal to "Changed Name", array[0].song becomes set to "Changed Name" also.
我遇到了问题，尽管我试图将 ONLY "theobject.song" 设置为等于 "Changed Name"，但 array[0].song 也设置为 "Changed Name"。
What I want is "theobject.song" to become "Changed Name" while array[0].song remains "The Song".
我想要的是“theobject.song”成为“Changed Name”，而array[0].song 仍然是“The Song”。
What is the best way to accomplish this?
实现这一目标的最佳方法是什么？
采纳答案by KooiInc
You will never get a reference to your object in the loop. Try:
您永远不会在循环中获得对您的对象的引用。尝试：
for(var i = 0; i < array.length; i++)
if(array[i].song === "The Song") {
theobject = array[i];
break;
}
That will give a reference to the object, and you will be able to change the objects songproperty.
这将提供对对象的引用，并且您将能够更改对象song属性。
If you want to use a copy of the object, then you'll have to do a manual copy. E.g.
如果要使用对象的副本，则必须进行手动复制。例如
function clone(obj) {
var copy = {};
for (var attr in obj) {
if (obj.hasOwnProperty(attr)) {
copy[attr] = obj[attr];
}
}
return copy;
}
And your loop becomes:
你的循环变成：
for(var i = 0; i < array.length; i++)
if(array[i].song === "The Song") {
theobject = clone(array[i]);
break;
}
回答by Tarik Chakur
It possible to use Object.assign() to only copy its value without the reference.
可以使用 Object.assign() 仅复制其值而无需引用。
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign
var array = [];
var theobject = null;
array.push({
song:"The Song",
artist:"The Artist"
},
{
song:"Another Song",
artist:"Another Artist"
});
for(var i = 0; i < array.length; i++)
if(array[i].song == "The Song") {
theobject = Object.assign( {}, array[i] );
break;
}
theobject.song = "Changed Name";
console.log( array );
console.log( theobject );