Question

Some javascript libraries are distributed as a fully concatenated file, including all of the dependent libraries. Some libraries like JQuery provide a way to handle conflicts if multiple version of the library are being used. But if a compiled/concatenated javascript file contains a library that doesn’t have a built in way of handling conflicts and I am using that same library (but a different version), is there a general way to wrap the version I am using and add a custom namespace to it? Or is that dependent on the library being used?

Answer 1

It depends on the library. If it provides all functions under one namespace, you can include your version first, store a reference to it under a different variable/name, (unset the original if conflict could occur) and include the other library afterwards.

It would look like this:

<script src="MyLibraryV1.js"></script>

<script>
    // Assuming all functions are available under `$`
    var MyLibraryV1 = $;
    // Now the next script can overwrite `$`. 
    // Optionally we can also delete/undefine this symbol:
   delete window.$;
</script>

<script src="OtherLibraryWithDependencies.js"></script>

<script>
    // For easy access, you can use an immediate function to still let `$` 
    // refer to your library version. It should not affect the other code
    // (but if it does you obviously have to use the other name)
    (function($) {
        // put all code that needs `MyLibraryV1` here
    }(MyLibraryV1));
</script>

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The better thing of course is if OtherLibraryWithDependencies would properly encapsulate all dependencies so that they don’t leak into global scope.