How to generate CRON expression in angular 12

[vivekdeshmukhrepos]

I know I am asking for reference and not actual code help here.

We have our own custom UI which has control onto it like- start time, end time, repeat on, each day etc. Now, by taking all those custom controls value we need to generate a CRON expression.

Can you please give any reference on how can we use this by passing our own UI elements values?