我有一个这样的数据结构:

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:

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

part1name应该用someObject.part1.name的值填充,即“Part 1”。part2quantity也是一样,它的容量是60。

有没有办法实现这与纯javascript或JQuery?


当前回答

使用下划线的属性或propertyOf:

Var检验= { foo: { 酒吧:{ 记者:“你好” } } } Var字符串= 'foo.bar.baz'; / / document . write (_.propertyOf(测试)(string.split (' . '))) document . write (_.property (string.split(' . '))(测试); < script src = " https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.9.1/underscore-min.js " > < /脚本>

祝你好运…

其他回答

// (IE9+) Two steps var pathString = "[0]['property'].others[3].next['final']"; var obj = [{ property: { others: [1, 2, 3, { next: { final: "SUCCESS" } }] } }]; // Turn string to path array var pathArray = pathString .replace(/\[["']?([\w]+)["']?\]/g,".$1") .split(".") .splice(1); // Add object prototype method Object.prototype.path = function (path) { try { return [this].concat(path).reduce(function (f, l) { return f[l]; }); } catch (e) { console.error(e); } }; // usage console.log(obj.path(pathArray)); console.log(obj.path([0,"doesNotExist"]));

这是我使用的解决方案:

function resolve(path, obj=self, separator='.') {
    var properties = Array.isArray(path) ? path : path.split(separator)
    return properties.reduce((prev, curr) => prev?.[curr], obj)
}

使用示例:

// accessing property path on global scope
resolve("document.body.style.width")
// or
resolve("style.width", document.body)

// accessing array indexes
// (someObject has been defined in the question)
resolve("part3.0.size", someObject) // returns '10'

// accessing non-existent properties
// returns undefined when intermediate properties are not defined:
resolve('properties.that.do.not.exist', {hello:'world'})

// accessing properties with unusual keys by changing the separator
var obj = { object: { 'a.property.name.with.periods': 42 } }
resolve('object->a.property.name.with.periods', obj, '->') // returns 42

// accessing properties with unusual keys by passing a property name array
resolve(['object', 'a.property.name.with.periods'], obj) // returns 42

限制:

不能将方括号([])用于数组下标-尽管在分隔符令牌之间指定数组下标(例如,.)可以正常工作,如上所示。

我只是基于一些类似的代码,我已经有了,它似乎工作:

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/上可以看到一个工作演示

有些人注意到,如果传递的字符串中最左边的索引与对象中正确嵌套的条目不对应,这段代码将抛出错误。这是一个有效的问题,但我认为最好在调用时使用try / catch块来解决,而不是让这个函数对于无效的索引无声地返回undefined。

现在有一个npm模块可以做到这一点:https://github.com/erictrinh/safe-access

使用示例:

var access = require('safe-access');
access(very, 'nested.property.and.array[0]');
/**
 * Access a deep value inside a object 
 * Works by passing a path like "foo.bar", also works with nested arrays like "foo[0][1].baz"
 * @author Victor B. https://gist.github.com/victornpb/4c7882c1b9d36292308e
 * Unit tests: http://jsfiddle.net/Victornpb/0u1qygrh/
 */
function getDeepVal(obj, path) {
    if (typeof obj === "undefined" || obj === null) return;
    path = path.split(/[\.\[\]\"\']{1,2}/);
    for (var i = 0, l = path.length; i < l; i++) {
        if (path[i] === "") continue;
        obj = obj[path[i]];
        if (typeof obj === "undefined" || obj === null) return;
    }
    return obj;
}

适用于

getDeepVal(obj,'foo.bar')
getDeepVal(obj,'foo.1.bar')
getDeepVal(obj,'foo[0].baz')
getDeepVal(obj,'foo[1][2]')
getDeepVal(obj,"foo['bar'].baz")
getDeepVal(obj,"foo['bar']['baz']")
getDeepVal(obj,"foo.bar.0.baz[1]['2']['w'].aaa[\"f\"].bb")