Function buildTextSearchFilter

buildTextSearchFilter(
    search: string,
    fields: string[],
):
    | { OR?: undefined }
    | { OR: { [key: string]: { contains: string; mode: "insensitive" } }[] }
Builds Prisma text search filter for multiple fields with case-insensitive matching.

This utility creates a Prisma where clause that searches for the given text across multiple specified fields using case-insensitive contains matching. It generates an OR condition that matches any of the specified fields, enabling flexible full-text search capabilities.
Parameters
- search: string
  Search term to look for
- fields: string[]
  Array of field names to search within
Returns
| { OR?: undefined }
| { OR: { [key: string]: { contains: string; mode: "insensitive" } }[] }
Prisma where clause object with OR conditions
Example
```
// Search across course name and description
const searchFilter = buildTextSearchFilter('javascript', ['name', 'description']);
// Returns: {
//   OR: [
//     { name: { contains: 'javascript', mode: 'insensitive' } },
//     { description: { contains: 'javascript', mode: 'insensitive' } }
//   ]
// }
```
Example
```
// Empty search or no fields returns empty object
const emptyFilter = buildTextSearchFilter('', ['name']);
// Returns: {}
```
- Defined in src/shared/middleware/pagination.ts:417