javascript如何查找对象中的子项数

Question

有没有办法找到javascript对象中的子项数,而不是运行循环和使用计数器？我可以利用jquery,如果它会有所帮助.我这样做:

var childScenesObj = [];
var childScenesLen = scenes[sceneID].length; //need to find number of children of scenes[sceneID]. This obviously does not work, as it an object, not an array.


for (childIndex in scenes[sceneID].children) {
    childSceneObj = new Object();
    childSceneID = scenes[sceneID].children[childIndex];
    childSceneNode = scenes[childSceneID];
    childSceneObj.name = childSceneNode.name;
    childSceneObj.id = childSceneID;
    childScenesObj  .push(childSceneObj);
}

Answer 1

以下适用于ECMAScript5(Javascript 1.85)

var x = {"1":1, "A":2};
Object.keys(x).length; //outputs 2