通过字符串路径访问嵌套的 JavaScript 对象和数组 [英] Accessing nested JavaScript objects and arrays by string path

问题描述

我有一个这样的数据结构:

I have a data structure like this :

var someObject = {
    'part1' : {
        'name': 'Part 1',
        'size': '20',
        'qty' : '50'
    },
    'part2' : {
        'name': 'Part 2',
        'size': '15',
        'qty' : '60'
    },
    'part3' : [
        {
            'name': 'Part 3A',
            'size': '10',
            'qty' : '20'
        }, {
            'name': 'Part 3B',
            'size': '5',
            'qty' : '20'
        }, {
            'name': 'Part 3C',
            'size': '7.5',
            'qty' : '20'
        }
    ]
};

我想使用这些变量访问数据:

And I would like to access the data using these variable :

var part1name = "part1.name";
var part2quantity = "part2.qty";
var part3name1 = "part3[0].name";

part1name 应填充 someObject.part1.name 的值，即第 1 部分".与填充 60 的 part2quantity 相同.

part1name should be filled with someObject.part1.name 's value, which is "Part 1". Same thing with part2quantity which filled with 60.

有没有办法用纯 javascript 或 JQuery 来实现这一点?

Is there anyway to achieve this with either pure javascript or JQuery?

推荐答案

我刚刚根据我已有的一些类似代码制作了这个，它似乎有效:

I just made this based on some similar code I already had, it appears to work:

Object.byString = function(o, s) {
    s = s.replace(/[(w+)]/g, '.$1'); // convert indexes to properties
    s = s.replace(/^./, '');           // strip a leading dot
    var a = s.split('.');
    for (var i = 0, n = a.length; i < n; ++i) {
        var k = a[i];
        if (k in o) {
            o = o[k];
        } else {
            return;
        }
    }
    return o;
}

用法::

Object.byString(someObj, 'part3[0].name');

在 http://jsfiddle.net/alnitak/hEsys/

EDIT 一些人已经注意到，如果传递一个字符串，其中最左边的索引不对应于对象中正确嵌套的条目，则此代码将引发错误.这是一个有效的问题，但恕我直言，最好在调用时使用 try/catch 块解决，而不是让此函数静默返回 undefined 以获取无效索引.

EDIT some have noticed that this code will throw an error if passed a string where the left-most indexes don't correspond to a correctly nested entry within the object. This is a valid concern, but IMHO best addressed with a try / catch block when calling, rather than having this function silently return undefined for an invalid index.

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