JavaScript object: access variable property by name as string
This question already has an answer here:
You don't need a function for it - simply use the bracket notation:
var side = columns['right'];
This is equal to dot notation, var side = columns.right; , except the fact that right could also come from a variable, function return value, etc., when using bracket notation.
If you NEED a function for it, here it is:
function read_prop(obj, prop) {
return obj[prop];
}
ThiefMaster's answer is 100% correct, although I came across a similar problem where I needed to fetch a property from a nested object (object within an object), so as an alternative to his answer, you can create a recursive solution that will allow you to define a nomenclature to grab any property, regardless of depth:
function fetchFromObject(obj, prop) {
if(typeof obj === 'undefined') {
return false;
}
var _index = prop.indexOf('.')
if(_index > -1) {
return fetchFromObject(obj[prop.substring(0, _index)], prop.substr(_index + 1));
}
return obj[prop];
}
Where your string reference to a given property ressembles property1.property2
Code and comments in JsFiddle.
由于我通过上面的答案帮助了我的项目（我提出了一个重复的问题，并在此处提及），因此在嵌套在var中时，我提交了括号表示法的答案（我的测试代码）：
<html>
<head>
<script type="text/javascript">
function displayFile(whatOption, whatColor) {
var Test01 = {
rectangle: {
red: "RectangleRedFile",
blue: "RectangleBlueFile"
},
square: {
red: "SquareRedFile",
blue: "SquareBlueFile"
}
};
var filename = Test01[whatOption][whatColor];
alert(filename);
}
</script>
</head>
<body>
<p onclick="displayFile('rectangle', 'red')">[ Rec Red ]</p>
<br/>
<p onclick="displayFile('square', 'blue')">[ Sq Blue ]</p>
<br/>
<p onclick="displayFile('square', 'red')">[ Sq Red ]</p>
</body>
</html>上一篇: 将PHP对象转换为关联数组