The code then makes a GET request to the /api/course API endpoint using the fetchWithCache function. This function appears to cache requests to reduce unnecessary API calls. It sends a query with the course's prefix and number as URL parameters (after encoding them for safety), for example, /api/course?prefix=CS&number=101.

The fetchWithCache function takes in three main arguments:

• The URL with query parameters.

• cacheIndexNebula: Likely an identifier for the cache.

• expireTime: Defines the time the cache expires.

• A configuration object specifying the request method (GET) and the accepted response type (application/json).

The first .then() block checks the response to ensure the API call was successful. If the message in the response is not 'success', an error is thrown.

If the response is successful, the next .then() block processes the actual data (CourseData[]), which is an array of course data.

The array of course data is sorted by the catalog_year property in descending order. This ensures that the most recent course information is placed at the beginning of the array (index 0).

It then sets the courseData state to { state: 'done', data: response[0] }, where response[0] is the most recent course data.

The code then makes a GET request to the /api/professor API endpoint using the fetchWithCache function. This function appears to cache requests to reduce unnecessary API calls. It sends a query with the Professor First and Last name as URL parameters (after encoding them for safety), for example, /api/professor?profFirst=John &profLast=Cole.

The fetchWithCache function takes in three main arguments:

• The URL with query parameters.

• cacheIndexNebula: Likely an identifier for the cache.

• expireTime: Defines the time the cache expires.

• A configuration object specifying the request method (GET) and the accepted response type (application/json).

The first .then() block checks the response to ensure the API call was successful. If the message in the response is not 'success', an error is thrown.

The state profData is then updated to:

• { state: 'done', data: response.data } if response.data is defined (indicating that professor data was successfully fetched).

• data: The actual professor data fetched from the API, which is cast to a ProfessorInterface type.

  • This part assigns the fetched professor data (response.data) to the data property.

  • The as ProfessorInterface part is a TypeScript type assertion, which explicitly tells TypeScript to treat response.data as if it conforms to the ProfessorInterface type. This ensures the data structure aligns with the expected format for a professor.