A Composable function that simplifies the process of providing a ViewModel in both runtime and preview environments.

PreviewOrHiltViewModel.kt

import androidx.compose.runtime.Composable
import androidx.compose.ui.platform.LocalInspectionMode
import androidx.hilt.navigation.compose.hiltViewModel
import androidx.lifecycle.ViewModel

/**
 * A Composable function that simplifies the process of providing a ViewModel in both
 * runtime and preview environments.
 *
 * In a standard runtime environment, it uses `hiltViewModel()` to retrieve a
 * Hilt-injected ViewModel instance.
 *
 * In a Compose preview environment (i.e., when `LocalInspectionMode.current` is true),
 * it returns a "fake" or mock instance of the ViewModel provided by the `fake` lambda.
 * This is useful for creating previews of Composables that depend on a ViewModel
 * without needing to set up the full Hilt dependency graph.
 *
 * @param VM The type of the ViewModel to be provided, which must extend [ViewModel].
 * @param fake A lambda function that returns a fake or mock instance of the ViewModel.
 *             This is only executed in preview mode.
 * @return The appropriate ViewModel instance for the current context (Hilt-injected or fake).
 *
 * @see [LocalInspectionMode]
 * @see [hiltViewModel]
 *
 * Example usage:
 * ```
 * @Composable
 * fun MyScreen(
 *     viewModel: MyViewModel = previewOrHiltViewModel {
 *         // This block is only called in preview mode
 *         MyViewModel(FakeRepository())
 *     }
 * ) {
 *     // Screen content that uses the viewModel
 * }
 *
 * @Preview
 * @Composable
 * fun MyScreenPreview() {
 *     MyApplicationTheme {
 *         MyScreen() // Will use the fake MyViewModel
 *     }
 * }
 * ```
 */
@Composable
inline fun <reified VM : ViewModel> previewOrHiltViewModel(
    fake: () -> VM
): VM {
    return if (LocalInspectionMode.current) {
        fake()
    } else {
        hiltViewModel<VM>()
    }
}