refactor(sns): simplify conditional display

[pidupuis]

I replaced every:

<% if(theme.sns.twitter == undefined){ %>
<% } else{ %>
...
<% } %>

by a simpler and more readable:

<% if(theme.sns.twitter){ %>
...
<% } %>

[Halyul]

I think this is unnecessary, because not every has his/her Twitter, Facebook account.
If you change this, the sns icons will always show on the footer. ( Just in my mind, hasnt tested.

[pidupuis]

I've tested it and it works the same because theme.sns.twitter returns false if nothing is set in the config for twitter.

I agree it does not work exactly the same because I exclude every falsy value, not only undefined.

Using

<% if(theme.sns.twitter == undefined){ %> 
<% } else { %>
... 
<% } %> 

is exactly the same as:

<% if(theme.sns.twitter != undefined){ %> 
... 
<% } %> 

which is already better.

It is even better to use the strict equality:

<% if(theme.sns.twitter !== undefined){ %> 
... 
<% } %> 

But with every one of these codes, a config containing:

facebook: "https://facebook.com/foo/bar"
twitter: false
linkedin:

would result by showing both facebook and twitter icons.

With my version, only the facebook icon would show up.

[Halyul]

OK, got it.