Cordova plugins undefined

Examining the config.xml and the JS file of cordova-plugin-zeroconf I found this declaration:

<js-module src="www/zeroconf.js" name="ZeroConf">
    <clobbers target="cambiocreative.CDVZeroConfig" />
</js-module>

So the plugin API should be available at this name space: cambiocreative.CDVZeroConfig

In fact as of Cordova Plugins documentation:

... tags are allowed within <js-module>:

<clobbers target="some.value"/> indicates that the module.exports is inserted into the window object as window.some.value. You can have as many <clobbers> as you like. Any object not available on window is created. ...

Probably the plugins that you are including dont use the cordova.plugin window. Just try to call the plugin functions, and check if they work.