How do you implement eager loading with conditions in Laravel

php
// In your controller or repository

// Eager load posts with only the approved favorites
$posts = Post::with(['favorites' => function ($query) {
    $query->where('approved', true);
}])->get();

// Eager load posts with only the favorites of the authenticated user
$posts = Post::with(['favorites' => function ($query) {
    $query->where('user_id', auth()->id());
}])->get();

// Eager load posts with only the approved favorites of the authenticated user
$posts = Post::with(['favorites' => function ($query) {
    $query->where('user_id', auth()->id())
          ->where('approved', true);
}])->get();

The key points are:

1. Use the `with()` method to eager load the desired relationship.
2. Pass a closure to the `with()` method, which allows you to add custom conditions to the eager loaded relationship query.
3. Inside the closure, you can use the `$query` parameter to add `where()`, `whereHas()`, or any other query constraints you need.

This way, you can eagerly load the related models (e.g. favorites) while also applying custom conditions to the eager loaded data. This helps avoid the N+1 query problem and allows you to fetch the data you need in a single, optimized database query.

Remember to replace `Post`, `favorites`, `user_id`, and `approved` with the appropriate model names, relationship names, and column names for your specific use case.