Why SC.ENVIRONMENT.customFieldsMetadata return undefined on cart page? and because of this above code is not working on cart page..

Because the SSP that is meant to load customFieldsMetadata is not loaded in the shopping application. I'm pretty sure this is a bug and I have created an issue ticket for it.

Thanks Steve

@Steve Goldberg Another request from my side regarding the above mentioned SSP - When we add around 10 or more SO custom fields in the Config record, customFieldsMetadata SSP is delaying the page load time. I think this need to be optimised for better performance or else the developers had to work on alternative solution for handling >10 custom fields. Thanks