function isEmpty( o ) {
    for ( var p in o ) { 
        if ( o.hasOwnProperty( p ) ) { return false; }
    }
    return true;
}

这是我的解决方案

function isEmpty(value) {
    if(Object.prototype.toString.call(value) === '[object Array]') {
        return value.length == 0;
    } else if(value != null && typeof value === 'object') {
        return Object.getOwnPropertyNames(value).length  == 0;
    } else {
        return !(value || (value === 0));
    }
}

解围球

也许你可以用这个决定:

var isEmpty = function(obj) {
  for (var key in obj)
    if(obj.hasOwnProperty(key))
      return false;
  return true;
}

假设你有以下对象:

var obj1= {};
var obj2= {test: "test"};

不要忘记我们不能使用===符号来测试对象是否相等，因为他们得到继承，所以如果你使用ECMA 5和更高版本的javascript，答案很简单，你可以使用下面的函数:

function isEmpty(obj) {
   //check if it's an Obj first
   var isObj = obj !== null 
   && typeof obj === 'object' 
   && Object.prototype.toString.call(obj) === '[object Object]';

   if (isObj) {
       for (var o in obj) {
           if (obj.hasOwnProperty(o)) {
               return false;
               break;
           }
       }
       return true;
   } else {
       console.error("isEmpty function only accept an Object");
   }
}

结果如下:

isEmpty(obj1); //this returns true
isEmpty(obj2); //this returns false
isEmpty([]); // log in console: isEmpty function only accept an Object

var hasOwnProperty = Object.prototype.hasOwnProperty;
function isArray(a) {
    return Object.prototype.toString.call(a) === '[object Array]'
}
function isObject(a) {
    return Object.prototype.toString.call(a) === '[object Object]'
}
function isEmpty(a) {
    if (null == a || "" == a)return!0;
    if ("number" == typeof a || "string" == typeof a)return!1;
    var b = !0;
    if (isArray(a)) {
        if (!a.length)return!0;
        for (var c = 0; c < a.length; c++)isEmpty(a[c]) || (b = !1);
        return b
    }
    if (isObject(a)) {
        for (var d in a)hasOwnProperty.call(a, d) && (isEmpty(a[d]) || (b = !1));
        return b
    }
    return!0
}

我修改了肖恩·维埃拉的代码来满足我的需要。Null和undefined根本不算作对象，数字、布尔值和空字符串返回false。

'use strict'; // Speed up calls to hasOwnProperty var hasOwnProperty = Object.prototype.hasOwnProperty; var isObjectEmpty = function(obj) { // null and undefined are not empty if (obj == null) return false; if(obj === false) return false; if(obj === true) return false; if(obj === "") return false; if(typeof obj === "number") { return false; } // Assume if it has a length property with a non-zero value // that that property is correct. if (obj.length > 0) return false; if (obj.length === 0) return true; // Otherwise, does it have any properties of its own? // Note that this doesn't handle // toString and valueOf enumeration bugs in IE < 9 for (var key in obj) { if (hasOwnProperty.call(obj, key)) return false; } return true; }; exports.isObjectEmpty = isObjectEmpty;