The code support (https://support.flowxo.com/article/145-code) provides information about utils.
I’m very surprise that Momentjs doesn’t make part of these tools, as it is availlable with Date & Time service as you specify :
“If you choose to edit this select box, you should give a date in the form e.g., DD-MM-YYYY. You can get further guidance on possible formats at http://momentjs.com/docs/#/displaying/format/”
Can you make MomentJs availlable (or maybe it is already) in code service, it would be an easyer way to format an array of date instead of adding “n” Date & Time service.