Why no semicolon at the end of js expression in javascriptmvc app?

Question

I am starting to learn javascriptmvc, and in code samples, I see code without semicolons at the end of expressions. Does this count on automatic semicolon insertion or am I missing something? Code example below:

$.Controller("Contacts.Controller", {
        init: function(){
            this.params = new Mxui.Data();
            $("#category .list_wrapper").mxui_data_list({
                model : Contacts.Models.Category,
                show : "//contacts/views/categoryList",
                create: "//contacts/views/categoryCreate"
            }) // <------ NO SEMICOLON

            $("#location .list_wrapper").mxui_data_list({
                model : Contacts.Models.Location,
                show : "//contacts/views/categoryList",
                create: "//contacts/views/categoryCreate"
            }) // <------ NO SEMICOLON

            $("#company .list_wrapper").mxui_data_list({
                model : Contacts.Models.Company,
                show : "//contacts/views/companyList",
                create: "//contacts/views/companyCreate"
            }) // <------ NO SEMICOLON
                            // etc...
         }
      }) // <------ NO SEMICOLON

possible duplicate of [Why use semicolon?](http://stackoverflow.com/questions/2399935/why-use-semicolon) — mplungjan, Jul 10 '11 at 17:07
Ditto [What are the rules for Javascript's automatic semicolon insertion?](http://stackoverflow.com/questions/2846283/what-are-the-rules-for-javascripts-automatic-semicolon-insertion) — mplungjan, Jul 10 '11 at 17:09
Semi-colons should be used after statements, not expressions. The addition of semi-colons to the code would explicitly make the subject lines statements. — RobG, Jul 10 '11 at 23:15

score 4 · Accepted Answer · answered Jul 10 '11 at 17:11

Javascript can be forgiving about the lack of a semicolon in ways that other languages are not. However a semicolon is recommended where you've pointed them out.

If you run the code you've given through JSLint, it throws up a whole stack of warnings, including complaining about those missing semicolons.

JSLint is a tool for telling you about things in your code which may not be syntax errors but which could cause problems. It generally throws up a lot of errors, even for relatively well written code, but it is good for picking up things which you should fix.

I would say that those code samples are poorly written because of the missing semi-colons.

I would say the semicolons were pointed out are not at all mandatory. — mplungjan, Jul 10 '11 at 17:45
@mplungjan - not mandatory, but recommended. If for no other reason than if you tried to minify that code, the lack of semicolons would cause it would break. — Spudley, Jul 10 '11 at 17:52

score 1 · Answer 2 · edited May 23 '17 at 11:48

1

Semicolons are only mandatory in inline event handlers. MOST anywhere else, a linefeed is enough. Here is an example of where it is not enough: Why is a semicolon required at end of line? And as pointed out, do not leave out semicolons if you want to minify your scripts.

edited May 23 '17 at 11:48

Community

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answered Jul 10 '11 at 17:06

mplungjan

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A linefeed is usually _not_ enough if the next line starts with a parenthesis. (e.g., `a = b + c[newline](d + e).print()` will require a semicolon somewhere on either side of `[newline]`.) – Ted Hopp Jul 10 '11 at 17:16
That link sort of says that, but not succinctly. Also, I wrote my comment while you were adding the link to your original post. Chalk it up to a time warp. :) – Ted Hopp Jul 10 '11 at 18:07

score 0 · Answer 3 · edited Nov 13 '20 at 08:33

0

A lot of semicolons are optional in javascript, though recommended to avoid confusion

https://mislav.net/2010/05/semicolons/

edited Nov 13 '20 at 08:33

Dave Powers

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answered Jul 10 '11 at 17:07

Nicklas A.

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Why no semicolon at the end of js expression in javascriptmvc app?

3 Answers3