safe upgrade on custom editviewdef

Hi all.

I have a custom module in which I included a js file (customjs.js) custom / modules / Cases / metadata / editviewdefs.php, I have created the installation package for the module loader, but I have a problem, since there is another module custom with the same configuration.

How can I do a safe installation to be able to include my js file without deleting the existing one?

thanks to everyone.

I'm working with Sugar 6.5.22