admin 管理员组

文章数量: 1086019

I'm trying to find a way to move an object element to a specific position.

For example, I've this object : 

{
    "element1" : {} // object,
    "element2" : {},
    "element3" : {}
}

And I search to move element3 at the first position : 

{
    "element3" : {},
    "element1" : {},
    "element2" : {}
}

Thanks for your help !

I'm trying to find a way to move an object element to a specific position.

For example, I've this object : 

{
    "element1" : {} // object,
    "element2" : {},
    "element3" : {}
}

And I search to move element3 at the first position : 

{
    "element3" : {},
    "element1" : {},
    "element2" : {}
}

Thanks for your help !

  • javascript
  • object
Share Improve this question asked Aug 12, 2014 at 9:38 amiceliamiceli 4555 gold badges12 silver badges29 bronze badges 1
  • 1 You can't do that. JavaScript objects don't have order. Use an array. – Ram Commented Aug 12, 2014 at 9:39
Add a ment  | 

3 Answers 3

Reset to default 4

JavaScript objects don't have ordering. You should use an array of objects instead.

var arr = [
  { id: 'element1' },
  { id: 'element2' },
  { id: 'element3' }
]

You could then reorder it something like:

var first = arr.splice(0, 1);
arr.push(first);

Maybe you could then grab specific elements based on id:

var out = arr.filter(function (el) {
  return el.id === 'element1';
});

Here's my code for doing that logic. Thanks!

function _moveElementObject(object, from, to) {
    var newObjects = [];
    var newObject = {};
    var oldObject = {};
    var firstObject = {};
    var lastObject = {};
    var toMoveKey = "";
    var toMoveValue;
    oldObject = object;
    var objLength = _countProperties(oldObject);
    var keyNo = 1;
    for (var key in oldObject) {
        if (keyNo == from) {
            toMoveKey = key;
            toMoveValue = oldObject[key];
        }
        keyNo++;
    }
    console.log(oldObject);

    keyNo = 1;
    for (var key in oldObject) {
        if (keyNo < to) {
            firstObject[key] = oldObject[key];
            newObject[key] = firstObject[key];
        }
        keyNo++;
    }
    console.log(firstObject);

    keyNo = 1;
    for (var key in oldObject) {
        if (to <= objLength) {
            lastObject[key] = oldObject[key];
        }
        keyNo++;
    }
    delete lastObject[toMoveKey];
    newObject[toMoveKey] = toMoveValue;

    for (var key in lastObject) {
        newObject[key] = lastObject[key];
    }
    console.log(newObject);
    console.log("push");
    return newObject;
}

var sampleObj = {
    "element1" : {} // object,
    "element2" : {},
    "element3" : {}
};

_moveElementObject(sampleObj,3,1);

// output object,
{
    "element3" : {},
    "element1" : {}, 
    "element2" : {},
}

Objects in JavaScript are essentially hash maps. Their properties don't have any ordering, per se. They are simply name value pairs.

You are probably confusing objects with arrays, in which case ordering does indeed matter.

本文标签： Move object element position in javascriptStack Overflow

版权声明：本文标题：Move object element position in javascript - Stack Overflow 内容由网友自发贡献，该文观点仅代表作者本人， 转载请联系作者并注明出处：http://www.roclinux.cn/p/1744086292a2531189.html， 本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌抄袭侵权/违法违规的内容，一经查实，本站将立刻删除。