It seems to be fashionable recently to omit semicolons from Javascript. There was a blog post a few years ago emphasising that in Javascript, semicolons are optional and the gist of the post seemed to be that you shouldn't bother with them because they're unnecessary. The post, widely cited, doesn't give any compelling reasons not to use them, just that leaving them out has few side-effects.

Even GitHub has jumped on the no-semicolon bandwagon, requiring their omission in any internally-developed code, and a recent commit to the zepto.js project by its maintainer has removed all semicolons from the codebase. His chief justifications were:


it's a matter of preference for his team;
less typing


Are there other good reasons to leave them out?

Frankly I can see no reason to omit them, and certainly no reason to go back over code to erase them. It also goes against (years of) recommended practice, which I don't really buy the "cargo cult" argument for. So, why all the recent semicolon-hate? Is there a shortage looming? Or is this just the latest Javascript fad?

I suppose my reason is the lamest: I program in too many different languages at the same time (Java, Javascript, PHP) - that require ';' so rather than train my fingers and eyes that the ';' is not needed for javascript, I just always add the ';'
The other reason is documentation: by adding the ';' I am explicitly stating to myself where I expect the statement to end. Then again I use { } all the time too.
The whole byte count argument I find irritating and pointless:

for common libraries like jquery: use the google CDN and the library will probably be in the browser cache already

version your own libraries and set them to be cached forever.

gzip and minimize if really, really necessary.


But really how many sites have as their biggest speed bottleneck the download speed of their javascript? If you work for a top 100 site like twitter, google, yahoo, etc. maybe. The rest of us should just worry about the code quality not semicolon religious wars.
