A simple way for JavaScript to determine whether an object {} is an empty object _javascript tips

When doing the project encountered a problem, to determine whether an object is empty object, found that this judgment can be, on the code:

1. Code 1:

var a = {};
if (!a) {console.log (1);}
else if (a = = null) {Console.log (2);} 
else {console.log (3);}

Results are: 3

2. Code 2:

var b = {};
if (b = = {}) {Console.log (4);}
if (b = = ' {} ') {Console.log (5);} 
if (typeof (b) = = ' object ') {Console.log (6);}

Results are: 6

3. Code 3:

var c = {};
if (json.stringify (c) = = "{}") {Console.log (7);}

var c = {};
if (json.stringify (c) = = "{}") {Console.log (7);}

Results are: 7

So you can use the method of code 3 to determine whether an object is an empty object {};

If the object is not empty, and you know that the object is not empty, an attribute (such as {id:111}) must exist, you can judge in this way:

4. Code 4:

var d = {};
var e = {id:111};
if (d.id) {Console.log (8);}
if (e.id) {Console.log (9);}

Results are: 9

Summary: obviously code 3 judgment way is more "strong", but the efficiency is obviously inferior to the Code 4 judgment method

The above is a small series for you to bring the JavaScript to determine whether an object {} is an empty object of the simple method of all content, I hope that we support the cloud Habitat Community ~