Javascript statement ending with comma or semicolon when object definition

Question

All, I am not familiar with the javascript OO, After I did some experiment with it ,I have some little confused questions about the object definition ,Please help to review my code and comments below.Thanks.

    GlobalUtility = function() {
            this.templeteCode = "123";

            this.Init();
//why can not put this code here,
//there is an error says GetOriginalSource is not a function . 
//This is not like the classical OO constructor which can call any methods in class.
            this.Init = function() {
                var source=this.GetOriginalSource();
                alert(source + " is ok.");
            },//I found I can end this statement by , or ; Is there any difference between them?

            this.GetOriginalSource=function(){
                return "abc";
            };
            //this.Init(); putting this code here is ok .

        };

I think that this question need to be moved to `codeReview` or `Programmers`. — Red, Mar 12 '13 at 10:11
Hi ,@Red , Where is the codeReview and Programmers .Could you please give me a link. Next time I will follow it .thanks. — Joe.wang, Mar 12 '13 at 10:13
http://programmers.stackexchange.com/?as=1 , http://codereview.stackexchange.com/?as=1 also check out the amazing stack sites. — Red, Mar 12 '13 at 10:30

score 4 · Accepted Answer · edited May 23 '17 at 11:45

4

You must define a function before calling it.
Semicolons in javascript are optional. Basically, a semicolon is used to end the statement while comma is when you working with objects. You could try reading these article JavaScript variable definition: Commas vs. Semicolons and Do you recommend using semicolons after every statement in JavaScript?

Javascript can be written in an oop way *see defining javascript class but i recommended to use Base.js, it will make your life easier.

You probably need this but it is not that fun to read :) javascript patterns

edited May 23 '17 at 11:45

Community

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answered Mar 12 '13 at 10:57

lngs

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If you are compressing your code, it is good to use semi-colon (;), hence the code could become something else, ex: var foo = 1var bar = 2; Also, when compressing, avoid // for comments, since it will comment the rest of the line to – Hiny Mar 12 '13 at 11:12

score 1 · Answer 2 · answered Mar 12 '13 at 10:29

try this:

GlobalUtility = function () {
            Init();


            this.templeteCode = "123";
            this.Init = Init;       
            this.GetOriginalSource = GetOriginalSource;

            //function declaration
            function Init() {
                var source = GetOriginalSource();
                alert(source + " is ok.");
            }
            function GetOriginalSource() {
                return "abc";
            }
};

You're trying to call a function that is not yet defined on runtime.

score 0 · Answer 3 · answered Mar 12 '13 at 10:12

0

this.GetOriginalSource=function(){ adds the function to the object. It is not there before this line. But you try to call it before.

answered Mar 12 '13 at 10:12

a better oliver

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Javascript statement ending with comma or semicolon when object definition

3 Answers3