Auto compile Javascript with Closure

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created June 28, 2010 · complexity basic · author Sternebrau · version 7.0

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This tip describes a simple way to automatically compile Javascript files using Google Closure. The compiled results are saved to a different file, for example, filename.js saves as both filename.js and filename.min.js.

The regular way

• Edit .js file
• Save .js file
• Link it in .html file
• Compile .js file
• Link compiled version in .html file
• Edit .js file
• Save .js file
• Forget to compile it
• Become frustrated because the compiled version is still linked in .html file

Using this tip

• Edit .js file
• Save .js file
• Link compiled version in .html
• Edit .js file
• Save .js file
• Test (because it's automatically compiled!)

Auto compile

Add this to your vimrc, while changing the path in "cpa" to suit your system:

autocmd BufWriteCmd *.js :call CompileJS()
function! CompileJS()
  if &modified
    write
    let fn = expand('%:p')
    let pn = expand('%:p:h')
    let fnm = expand('%:r.js')
    let cpa = '/home/username/closure/compiler.jar'
    execute "! java -jar " . cpa . " --js=" . fn . " --js_output_file=" . pn . "/" . fnm . ".min.js"
  endif
endfunction