I’m currently developing a habit tracker application using MongoDB and Next.js, and I’m facing an issue with creating instances of habits for users. Here’s a brief overview of my current setup:

I have three collections in my MongoDB database:

Users: Contains user information.

Habits: Contains details about habits such as habit name, description, frequency (daily or specific days of the week), and time.

HabitInstances: Contains instances of habits for specific dates, with fields for user ID, habit ID, date, and status (completed or not).

When a user adds a new habit, it is saved in the Habits collection. Here is an example of a habit:

The challenge I’m facing is efficiently generating instances of these habits for the next 30 days without creating them indefinitely. For instance, if a user wants to repeat a habit every Monday, Tuesday, and Wednesday, I need to create instances for the next 30 days so that when the user checks the app, they can see their habits scheduled for those specific days.

Creating these instances indefinitely would be inefficient and could lead to performance issues, especially with many users.

Could anyone provide a detailed explanation or example of how to generate these habit instances for the next 30 days based on the habit’s frequency? Any guidance on implementing this in MongoDB and Next.js would be greatly appreciated.

Thank you!