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

mohamed Hamouday' Answer的扩展将填补缺失的关键

function Object_Manager(obj, Path, value, Action, strict) 
{
    try
    {
        if(Array.isArray(Path) == false)
        {
            Path = [Path];
        }

        let level = 0;
        var Return_Value;
        Path.reduce((a, b)=>{
            console.log(level,':',a, '|||',b)
            if (!strict){
              if (!(b in a)) a[b] = {}
            }


            level++;
            if (level === Path.length)
            {
                if(Action === 'Set')
                {
                    a[b] = value;
                    return value;
                }
                else if(Action === 'Get')
                {
                    Return_Value = a[b];
                }
                else if(Action === 'Unset')
                {
                    delete a[b];
                }
            } 
            else 
            {
                return a[b];
            }
        }, obj);
        return Return_Value;
    }

    catch(err)
    {
        console.error(err);
        return obj;
    }
}

例子


obja = {
  "a": {
    "b":"nom"
  }
}

// Set
path = "c.b" // Path does not exist
Object_Manager(obja,path.split('.'), 'test_new_val', 'Set', false);

// Expected Output: Object { a: Object { b: "nom" }, c: Object { b: "test_new_value" } }

其他回答

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'

在这里我提供了更多的方法,这些方法在很多方面看起来都更快:

选项1:Split string on。Or [Or] Or ' Or ",颠倒过来,跳过空项。

function getValue(path, origin) {
    if (origin === void 0 || origin === null) origin = self ? self : this;
    if (typeof path !== 'string') path = '' + path;
    var parts = path.split(/\[|\]|\.|'|"/g).reverse(), name; // (why reverse? because it's usually faster to pop off the end of an array)
    while (parts.length) { name=parts.pop(); if (name) origin=origin[name]; }
    return origin;
}

选项2(最快的,除了eval):低级字符扫描(没有regex/split/等等,只是一个快速字符扫描)。 注意:该命令不支持索引引用。

function getValue(path, origin) {
    if (origin === void 0 || origin === null) origin = self ? self : this;
    if (typeof path !== 'string') path = '' + path;
    var c = '', pc, i = 0, n = path.length, name = '';
    if (n) while (i<=n) ((c = path[i++]) == '.' || c == '[' || c == ']' || c == void 0) ? (name?(origin = origin[name], name = ''):(pc=='.'||pc=='['||pc==']'&&c==']'?i=n+2:void 0),pc=c) : name += c;
    if (i==n+2) throw "Invalid path: "+path;
    return origin;
} // (around 1,000,000+/- ops/sec)

选项3:(新:选项2扩展到支持引号-有点慢,但仍然很快)

function getValue(path, origin) {
    if (origin === void 0 || origin === null) origin = self ? self : this;
    if (typeof path !== 'string') path = '' + path;
    var c, pc, i = 0, n = path.length, name = '', q;
    while (i<=n)
        ((c = path[i++]) == '.' || c == '[' || c == ']' || c == "'" || c == '"' || c == void 0) ? (c==q&&path[i]==']'?q='':q?name+=c:name?(origin?origin=origin[name]:i=n+2,name='') : (pc=='['&&(c=='"'||c=="'")?q=c:pc=='.'||pc=='['||pc==']'&&c==']'||pc=='"'||pc=="'"?i=n+2:void 0), pc=c) : name += c;
    if (i==n+2 || name) throw "Invalid path: "+path;
    return origin;
}

JSPerf: http://jsperf.com/ways-to-dereference-a-delimited-property-string/3

"eval(...)" is still king though (performance wise that is). If you have property paths directly under your control, there shouldn't be any issues with using 'eval' (especially if speed is desired). If pulling property paths "over the wire" (on the line!? lol :P), then yes, use something else to be safe. Only an idiot would say to never use "eval" at all, as there ARE good reasons when to use it. Also, "It is used in Doug Crockford's JSON parser." If the input is safe, then no problems at all. Use the right tool for the right job, that's it.

我已经看了所有其他的答案,决定在更可读的代码中添加改进:

function getObjectValByString(obj, str) {
if (typeof obj === "string") return obj;

const fields = str.split(".");

return getObjectValByString(obj[fields[0]], fields.slice(1).join("."));}

下面是一个代码片段:

let someObject = { 合作伙伴:{ id:“目标”, 人:{ 名称:“蚂蚁”, an:{名称:“ESM”}, }, }, }; 函数getObjectValByString(obj, str) { If (typeof obj === "string")返回obj; Const fields = str.split("."); 返回getObjectValByString(obj[fields[0]], fields.slice(1).join(".")); } const result = getObjectValByString(someObject, "partner.person.an.name"); console.log ({ 结果, });

简单的函数,允许字符串或数组路径。

function get(obj, path) {
  if(typeof path === 'string') path = path.split('.');

  if(path.length === 0) return obj;
  return get(obj[path[0]], path.slice(1));
}

const obj = {a: {b: {c: 'foo'}}};

console.log(get(obj, 'a.b.c')); //foo

OR

console.log(get(obj, ['a', 'b', 'c'])); //foo

我正在用React开发网上商店。我尝试在复制的状态对象中更改值,以在提交时更新原始状态。 上面的例子没有为我工作,因为他们中的大多数突变复制对象的结构。我找到了访问和更改深嵌套对象属性值的函数的工作示例:https://lowrey.me/create-an-object-by-path-in-javascript-2/

const createPath = (obj, path, value = null) => {
  path = typeof path === 'string' ? path.split('.') : path;
  let current = obj;
  while (path.length > 1) {
    const [head, ...tail] = path;
    path = tail;
    if (current[head] === undefined) {
      current[head] = {};
    }
    current = current[head];
  }
  current[path[0]] = value;
  return obj;
};