如何测试一个空的JavaScript对象？

ECMA 5+:

// because Object.keys(new Date()).length === 0;// we have to do some additional checkObject.keys(obj).length === 0 && obj.constructor === Object

Note, though, that this creates an unnecessary array (the return value of keys).

Pre-ECMA 5:

function isEmpty(obj) {  for(var prop in obj) {    if(obj.hasOwnProperty(prop)) {      return false;    }  }  return JSON.stringify(obj) === JSON.stringify({});}

jQuery:

jQuery.isEmptyObject({}); // true

lodash:

_.isEmpty({}); // true

Underscore:

_.isEmpty({}); // true

Hoek

Hoek.deepEqual({}, {}); // true

ExtJS

Ext.Object.isEmpty({}); // true

AngularJS (version 1)

angular.equals({}, {}); // true

Ramda

R.isEmpty({}); // true