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

这可能永远都不会曝光……但不管怎样，它在这里。

将[]括号语法替换为。继续前进。字符删除空白字符串找到路径(否则未定义)

(为了找到一个对象的路径，使用这个pathTo解决方案。)

// "one liner" (ES6) const deep_value = (obj, path) => path .replace(/\[|\]\.?/g, '.') .split('.') .filter(s => s) .reduce((acc, val) => acc && acc[val], obj); // ... and that's it. 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' } // ... ], 'pa[rt3' : [ { 'name': 'Part 3A', 'size': '10', 'qty' : '20' } // ... ] }; console.log(deep_value(someObject, "part1.name")); // Part 1 console.log(deep_value(someObject, "part2.qty")); // 60 console.log(deep_value(someObject, "part3[0].name")); // Part 3A console.log(deep_value(someObject, "part3[0].....name")); // Part 3A - invalid blank paths removed console.log(deep_value(someObject, "pa[rt3[0].name")); // undefined - name does not support square brackets

2018-06-26 18:16:45

其他回答

根据Alnitak的回答:

if(!Object.prototype.byString){
  //NEW byString which can update values
Object.prototype.byString = function(s, v, o) {
  var _o = o || this;
      s = s.replace(/\[(\w+)\]/g, '.$1'); // CONVERT INDEXES TO PROPERTIES
      s = s.replace(/^\./, ''); // STRIP A LEADING DOT
      var a = s.split('.'); //ARRAY OF STRINGS SPLIT BY '.'
      for (var i = 0; i < a.length; ++i) {//LOOP OVER ARRAY OF STRINGS
          var k = a[i];
          if (k in _o) {//LOOP THROUGH OBJECT KEYS
              if(_o.hasOwnProperty(k)){//USE ONLY KEYS WE CREATED
                if(v !== undefined){//IF WE HAVE A NEW VALUE PARAM
                  if(i === a.length -1){//IF IT'S THE LAST IN THE ARRAY
                    _o[k] = v;
                  }
                }
                _o = _o[k];//NO NEW VALUE SO JUST RETURN THE CURRENT VALUE
              }
          } else {
              return;
          }
      }
      return _o;
  };

}

这也允许你设置一个值!

我已经用这个创建了一个npm包和github

2017-08-02 19:16:40

使用eval:

var part1name = eval("someObject.part1.name");

换行以在错误时返回undefined

function path(obj, path) {
    try {
        return eval("obj." + path);
    } catch(e) {
        return undefined;
    }
}

http://jsfiddle.net/shanimal/b3xTw/

在使用评估的权力时，请使用常识和谨慎。它有点像光剑，如果你打开它，有90%的几率你会切断一个肢体。并不是每个人都适合。

2012-12-20 14:13:31

AngularJS有$scope.$eval

在AngularJS中，我们可以使用$scope。$eval方法访问嵌套对象:

$scope.someObject = someObject;
console.log( $scope.$eval("someObject.part3[0].name") ); //Part 3A

有关更多信息，请参见

AngularJS $scope API引用- $eval

演示

angular.module("app",[]) .run(function($rootScope) { $rootScope.someObject = { 'part2' : { 'name': 'Part 2', 'size': '15', 'qty' : '60' }, 'part3' : [{ 'name': 'Part 3A', 'size': '10', 'qty' : '20' },{ name: 'Part 3B' }] }; console.log( "part3[0].name =", $rootScope.$eval("someObject.part3[0].name") ); }) <script src="//unpkg.com/angular/angular.js"></script> <body ng-app="app" </body>

2020-03-05 20:09:28

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

/**
 * 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")

2016-03-01 17:05:57

通过字符串路径访问嵌套的JavaScript对象和数组

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