Forum: Ruby on Rails -%> (hyphen character) in .js.erb

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 10:27 PM (1 minute ago)
  When I run rake assets:precompile on my app, I get the following 
error:

syntax error, unexpected tSTRING_BEG, expecting 
keyword_end_erbout.concat
"\n"

which refers to a line in a .js.erb file ending in -%>.

The ending hyphen was added to eliminate the line break in .html.erb 
files.
But when I remove the hyphen, the error goes away. The last sentence 
ofsection'2.2.1
CSS and ERB' in 
<http://guides.rubyonrails.org/asset_pipeline.html>...
says 'Note that the closing tag cannot be of the style -%>.' Does anyone
know why adding the dash before %> in .js.erb (and apparently in 
.css.erb)
files causes the rails precompiler to fail?

Thanks!

shellz wrote in post #1095771:
> syntax error, unexpected tSTRING_BEG, expecting
> keyword_end_erbout.concat
> "\n"
>
> which refers to a line in a .js.erb file ending in -%>.
>
> The ending hyphen was added to eliminate the line break in .html.erb
> files.
> But when I remove the hyphen, the error goes away. The last sentence
> ofsection'2.2.1
> CSS and ERB' in
> 
<http://guides.rubyonrails.org/asset_pipeline.html>...
> says 'Note that the closing tag cannot be of the style -%>.' Does anyone
> know why adding the dash before %> in .js.erb (and apparently in
> .css.erb)
> files causes the rails precompiler to fail?

Because using -%> causes a syntax error, unexpected tSTRING_BEG to 
occur.

<<<Damn that was a smart-ass reply. Shame on me>>>

In my quick test case I got a syntax error, unexpected ')'
...rbout.concat(( 'Hello World' -).to_s); _erbout.concat "\");\...

Notice that the dash is still there trying to be concatenated in.

I don't really know exactly why, but it's obvious you cannot use -%> in 
js.erb or css.erb, so don't do it and your code wont fail.

See the last sentence of section 2.2.1 of the Asset Pipeline guide: 
http://guides.rubyonrails.org/asset_pipeline.html

Sorry, that was redundant.

It's because -%> needs to know how to remove whitespace from within the 
file itself, parsing & reading the content outside the replacement 
content. I don't know for sure but I'll bet the explanation is simply 
that this is too complicated in these pipeline files because whitespace 
works differently.