Prepare script to compile in JavaScript compiler (Google Closure)

I have code written in many places. I want to refactor the code to be able to use JavaScript compiler for performance and syntax check reasons. What is the recommendation to prepare the code for compiling?

• I have JavaScript code written with EJS to render some server-side data in JavaScript:

Code:

<% if(product.type){ %>
        $('#someid').html('<%= product.type %>');   //javascript
<% } %>

• I think the compiler will change my variables name (I know it can be set not to change which variable, but I have so many of them used across the pages, scripts, or widgets/subpages; something like global var), in that case it'll surely collapse my code.

I've heard that writing in closure style 开发者_如何转开发helps variable collision between each script files. Do I have to rewrite all code using that pattern? Do I have to construct the code from scatch? I'm asking for the way to prepare the code to be compiled, any suggestion?

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The compiler does not change global and property names. It just renames the local variables and removes the whitespace.