will nodejs global variables lead memory leak?

Question

I notice react native demo code always show below usage.

const styles = StyleSheet.create({
// ... some styles
});

I'm newbie that don't deeply understand memory management of GC, but if in above way, will variable styles be freed? if so, when?

I think this styles is global variable in this module, and I'm not sure that whether do below method maybe better..

this.styles = StyleSheet.create();  // in the module.exports

will anybody provide any suggestions?

thanks for your time.