如何循环遍历JavaScript对象中的所有成员,包括作为对象的值?

例如,我如何循环(分别访问“your_name”和“your_message”)?

var validation_messages = {
    "key_1": {
        "your_name": "jimmy",
        "your_msg": "hello world"
    },
    "key_2": {
        "your_name": "billy",
        "your_msg": "foo equals bar"
    }
}

当前回答

使用Undercore.js的_.each:

_.each(validation_messages, function(value, key){
    _.each(value, function(value, key){
        console.log(value);
    });
});

其他回答

我无法得到之前的答案来做我想要的事情。

在玩弄了这里的其他回复之后,我做了这个。它很粗糙,但很管用!

对于此对象:

var myObj = {
    pageURL    : "BLAH",
    emailBox   : {model:"emailAddress", selector:"#emailAddress"},
    passwordBox: {model:"password"    , selector:"#password"}
};

…此代码:

// Get every value in the object into a separate array item ...
function buildArray(p_MainObj, p_Name) {
    var variableList = [];
    var thisVar = "";
    var thisYes = false;
    for (var key in p_MainObj) {
       thisVar = p_Name + "." + key;
       thisYes = false;
       if (p_MainObj.hasOwnProperty(key)) {
          var obj = p_MainObj[key];
          for (var prop in obj) {
            var myregex = /^[0-9]*$/;
            if (myregex.exec(prop) != prop) {
                thisYes = true;
                variableList.push({item:thisVar + "." + prop,value:obj[prop]});
            }
          }
          if ( ! thisYes )
            variableList.push({item:thisVar,value:obj});
       }
    }
    return variableList;
}

// Get the object items into a simple array ...
var objectItems = buildArray(myObj, "myObj");

// Now use them / test them etc... as you need to!
for (var x=0; x < objectItems.length; ++x) {
    console.log(objectItems[x].item + " = " + objectItems[x].value);
}

…在控制台中生成:

myObj.pageURL = BLAH
myObj.emailBox.model = emailAddress
myObj.emailBox.selector = #emailAddress
myObj.passwordBox.model = password
myObj.passwordBox.selector = #password

每个2

(在此处找到):

var lunch = {
    sandwich: 'ham',
    age: 48,
};
lunch.forEach2(function (item, key) {
    console.log(key);
    console.log(item);
});

代码:

if (!Object.prototype.forEach2) {
    Object.defineProperty(Object.prototype, 'forEach2', {
        value: function (callback, thisArg) {
            if (this == null) {
                throw new TypeError('Not an object');
            }
            thisArg = thisArg || window;
            for (var key in this) {
                if (this.hasOwnProperty(key)) {
                    callback.call(thisArg, this[key], key, this);
                }
            }
        }
    });
}

有很多方法可以遍历对象。请查看以下示例。

var obj = {'name':'John Doe','email':'johndoe@example.com'}

方法1

var keys = Object.keys(obj)
for(var i= 0; i < keys.length;i++){
  console.log(keys[i]+ ': ' + obj[keys[i]])
}

方法2

for(var key in obj){
  console.log(key+': '+ obj[key])
}

方法3

Object.keys(obj).forEach(function (key) {
  console.log(key+ ': ' + obj[key])
})

有几种方法可以做到这一点。。。

1) 两层的。。。循环中。。。

for (let key in validation_messages) {
   const vmKeys = validation_messages[key];
   for (let vmKey in vmKeys) {
      console.log(vmKey + vmKeys[vmKey]);
   }
}

2) 使用Object.key

Object.keys(validation_messages).forEach(key => {
   const vmKeys = validation_messages[key];
   Object.keys(vmKeys).forEach(key => {
    console.log(vmKeys + vmKeys[key]);
   });
});

3) 递归函数

const recursiveObj = obj => {
  for(let key in obj){
    if(!obj.hasOwnProperty(key)) continue;

    if(typeof obj[key] !== 'object'){
      console.log(key + obj[key]);
    } else {
      recursiveObj(obj[key]);
    }
  }
}

并将其称为:

recursiveObj(validation_messages);

2020年,您需要不可变的通用函数

这将遍历由子对象、数组和字符串组成的多维对象,并应用自定义函数:

export const iterate = (object, func) => {
  const entries = Object.entries(object).map(([key, value]) =>
    Array.isArray(value)
      ? [key, value.map(e => iterate(e, func))]
      : typeof value === 'object'
      ? [key, iterate(value, func)]
      : [key, func(value)]
  );
  return Object.fromEntries(entries);
};

用法:

const r = iterate(data, e=>'converted_'+e);
console.log(r);