通过字符串路径访问嵌套的JavaScript对象和数组

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

最近遇到了同样的问题，并且成功地使用了https://npmjs.org/package/tea-properties，它也设置了嵌套对象/数组:

get:

var o = {
  prop: {
    arr: [
      {foo: 'bar'}
    ]
  }
};

var properties = require('tea-properties');
var value = properties.get(o, 'prop.arr[0].foo');

assert(value, 'bar'); // true

set:

var o = {};

var properties = require('tea-properties');
properties.set(o, 'prop.arr[0].foo', 'bar');

assert(o.prop.arr[0].foo, 'bar'); // true

2013-10-25 19:33:20

其他回答

这个解决方案怎么样:

setJsonValue: function (json, field, val) {
  if (field !== undefined){
    try {
      eval("json." + field + " = val");
    }
    catch(e){
      ;
    }
  }  
}

这个，用来得到:

getJsonValue: function (json, field){
  var value = undefined;
  if (field !== undefined) {
    try {
      eval("value = json." + field);
    } 
    catch(e){
      ;
    }
  }
  return value;
};

可能有些人会认为它们不安全，但它们解析字符串的速度肯定要快得多。

2013-12-04 19:54:04

我认为你的要求是:

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

你可以这样问:

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

这两种方法都可行

也许这是你自找的

var partName = "part1";
var nameStr = "name";

var part1name = someObject[partName][nameStr];

终于轮到你自找麻烦了

var partName = "part1.name";

var partBits = partName.split(".");

var part1name = someObject[partBits[0]][partBits[1]];

2011-06-27 10:28:27

现在lodash使用_支持这一点。get (obj,财产)。看到https://lodash.com/docs

文档中的例子:

var object = { 'a': [{ 'b': { 'c': 3 } }] };

_.get(object, 'a[0].b.c');
// → 3

_.get(object, ['a', '0', 'b', 'c']);
// → 3

_.get(object, 'a.b.c', 'default');
// → 'default'

2015-07-08 20:59:00

从@Alnitak answer开始，我构建了这个源代码，它下载了一个实际的.JSON文件并对其进行处理，为每一步打印到控制台解释字符串，以及在传递错误键的情况下的更多细节:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
  <script>
function retrieveURL(url) {
        var client = new XMLHttpRequest();
        prefix = "https://cors-anywhere.herokuapp.com/"
        client.open('GET', prefix + url);
        client.responseType = 'text';
        client.onload = function() {
            response = client.response; // Load remote response.
            console.log("Response received.");
            parsedJSON  = JSON.parse(response);
            console.log(parsedJSON);
            console.log(JSONitemByPath(parsedJSON,"geometry[6].obs[3].latituade"));
            return response;
        };
        try {
            client.send();
        } catch(e) {
            console.log("NETWORK ERROR!");
            console.log(e);
        }
}



function JSONitemByPath(o, s) {
    structure = "";
    originalString = s;
    console.log("Received string: ", s);
    s = s.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
    console.log("Converted to   : ", s);
    s = s.replace(/^\./, '');           // strip a leading dot
    var a = s.split('.');

    console.log("Single keys to parse: ",a);

    for (var i = 0, n = a.length; i < n; ++i) {
        var k = a[i];
        if (k in o) {
            o = o[k];
            console.log("object." + structure +  a[i], o);
            structure +=  a[i] + ".";
        } else {
            console.log("ERROR: wrong path passed: ", originalString);
            console.log("       Last working level: ", structure.substr(0,structure.length-1));
            console.log("       Contents: ", o);
            console.log("       Available/passed key: ");
            Object.keys(o).forEach((prop)=> console.log("       "+prop +"/" + k));
            return;
        }
    }
    return o;
}


function main() {
    rawJSON = retrieveURL("http://haya2now.jp/data/data.json");
}

</script>
  </head>
  <body onload="main()">
  </body>
</html>

输出的例子:

Response received.
json-querier.html:17 {geometry: Array(7), error: Array(0), status: {…}}
json-querier.html:34 Received string:  geometry[6].obs[3].latituade
json-querier.html:36 Converted to   :  geometry.6.obs.3.latituade
json-querier.html:40 Single keys to parse:  (5) ["geometry", "6", "obs", "3", "latituade"]
json-querier.html:46 object.geometry (7) [{…}, {…}, {…}, {…}, {…}, {…}, {…}]
json-querier.html:46 object.geometry.6 {hayabusa2: {…}, earth: {…}, obs: Array(6), TT: 2458816.04973593, ryugu: {…}, …}
json-querier.html:46 object.geometry.6.obs (6) [{…}, {…}, {…}, {…}, {…}, {…}]
json-querier.html:46 object.geometry.6.obs.3 {longitude: 148.98, hayabusa2: {…}, sun: {…}, name: "DSS-43", latitude: -35.4, …}
json-querier.html:49 ERROR: wrong path passed:  geometry[6].obs[3].latituade
json-querier.html:50        Last working level:  geometry.6.obs.3
json-querier.html:51        Contents:  {longitude: 148.98, hayabusa2: {…}, sun: {…}, name: "DSS-43", latitude: -35.4, …}
json-querier.html:52        Available/passed key: 
json-querier.html:53        longitude/latituade
json-querier.html:53        hayabusa2/latituade
json-querier.html:53        sun/latituade
json-querier.html:53        name/latituade
json-querier.html:53        latitude/latituade
json-querier.html:53        altitude/latituade
json-querier.html:18 undefined

2019-11-28 13:38:11

基于前面的回答，我创建了一个也可以处理括号的函数。但由于裂开，里面没有点。

function get(obj, str) {
  return str.split(/\.|\[/g).map(function(crumb) {
    return crumb.replace(/\]$/, '').trim().replace(/^(["'])((?:(?!\1)[^\\]|\\.)*?)\1$/, (match, quote, str) => str.replace(/\\(\\)?/g, "$1"));
  }).reduce(function(obj, prop) {
    return obj ? obj[prop] : undefined;
  }, obj);
}

2017-11-01 12:44:48

通过字符串路径访问嵌套的JavaScript对象和数组

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