If depend on A and B and both A and B depend on the same version range as C, C is now a top-level dependency.

Your node_modules will look like this:

    - Package_A
    - Package_B
    - Package_C

It's only when A and B depend on different versions of C that cannot be resolved via semver as safe.

    - Package_A
    -- node_modules
    --- Package_C
    - Package_B
    -- node_modules
    --- Package_C

I am pretty certain that monkey patching your dependencies is frowned upon in the Node world. It's best to fork the repo make your changes, and then depend on that.