{"id":2610,"date":"2017-06-19T09:00:55","date_gmt":"2017-06-19T03:30:55","guid":{"rendered":"https:\/\/code4developers.com\/?p=2610"},"modified":"2018-09-04T20:50:19","modified_gmt":"2018-09-04T15:20:19","slug":"semicolon-in-javascript","status":"publish","type":"post","link":"https:\/\/code4developers.com\/semicolon-in-javascript\/","title":{"rendered":"Importance of Semicolon [;] In JavaScript"},"content":{"rendered":"

It is said that in JavaScript semicolons are not compulsory. It’s true, because JavaScript automatically inserts a semicolons at required place and it is know as “Automatic Semicolon Insertion”<\/strong>. This behavior of JavaScript confuses us a lot. This article is written for those who have just started writing JavaScript and for those who don\u2019t know the “Automatic insertion of semicolon in JavaScript<\/strong>“.<\/p>\n

<\/p>\n

function function1() {  \r\n    return {  \r\n        a: 10  \r\n    };  \r\n} \r\n\r\nfunction function2() {   \r\n    return \r\n    {  \r\n        a: 10  \r\n    };  \r\n}<\/pre>\n
At first look, the code given above looks same but look at the output given below.<\/p>\n
Console.log(function1());\r\n\r\nOutput:\r\n\r\nObject { a: 10 }\r\n\r\n<\/pre>\n
Console.log(function2());\r\n\r\nOutput:\r\n\r\nundefined<\/pre>\n
It is quite surprising that function2() returns undefined without any error being thrown.<\/p>\n
The reason behind the function returning undefined is the fact that in JavaScript semicolons are optional (although it is not a good practice to ignore them). Hence, when the line with the return statement is executed in function2(), it automatically places a semicolon immediately at the end of the return statement. In this case, no error is thrown as the remainder is perfectly valid, even though it is not invoked and doesn’t do anything.<\/p>\n
This behavior also suggests following the convention of placing an opening curly brace at the end of the same line and not at the new line.<\/p>\n
Following statements must be terminated with the semicolons<\/strong><\/h4>\n