Introduction

In this article i’ll show you how to use when() method in a Laravel application as an alternative to the typical/traditional conditional (if-else) statements/blocks in PHP.

Typical if-else use case

        $query = Post::query();

        if ($request->title == 'Laravel Eloquent Queries') {
            $query->where('title', $request->title);
        }
        $posts = $query->latest()->get();

What is when() method?

The when() method in Laravel is an easy way to apply condition to a query or collection to determine what block of code to execute when the condition evaluates to be true without having to use complex if-else conditional statements or blocks.

when() method syntax

$query->when($request->has('title'), function ($query) use ($request) {
    return $query->where('title', $request->title);
});

Breakdown of when() syntax

• condition: the first argument of the when() syntax as shown in the code above $request->has('title') is the condition which will evaluated to return a boolean value. If the name is present on the request it automatically executes the code of block else it skips the code of block.

• Callback: the callback closure executes if the condition is satisfied to be true or false as defined by the developer. For example !$request->has('title') simply checks if the name is not available on the request and proceeds which is different from checking if it exist $request->has('title').

• Optional Callback: An optional callback can be defined to be executed if the first condition is not satisfied.

when() method in Action

• Execute the callback if the request has an active parameter and is holds a true value

//return posts with status of true
        $posts = Post::when($request->has('active'), function ($query) {
            return $query->where('status', true);
        })->get();

• Execute the callback if the request does not have an active variable and is false

$posts = Post::when($request->has('active'), function ($query) {
            return $query->where('status', true);
        }, function ($query) {
            return $query->where('status', false);
        })->get();

• How to use multiple when() method

  $validator = Validator::make($request->all(), [
        'title' => 'nullable|string|max:10',
        'content' => 'nullable|string|max:10',
    ]);
    // Check if validation fails
    if ($validator->fails()) {
//         return validation errors 
    }
 $posts = Post::when($request->has('title'), function ($query) use ($request) {
            return $query->where('title', 'LIKE', "%{$request->title}%");
        })->when($request->has('content'), function ($query) use ($request) {
            return $query->where('content', 'LIKE', "%{$request->content}%");
        })->get();

whenEmpty()

        $posts = Post::when($request->has('active'), function ($query) {
            return $query->where('status', true);
        })->get()
        ->whenEmpty(function () {
            //this section will be executed if the posts result is empty
            //You could return a default array
            // return ;
        });

whenNotEmpty()

For example: Let’s assume you want to apply the first letter uppercase transformation to the title column when the posts collection is not empty.

Probably you want to take care of the modification within the controller method without having to do {{ ucwords($post->title) }} in the blade file. There could be more advanced reasons to do this other than just applying uppercase function.

        $posts = Post::when($request->has('active'), function ($query) {
            return $query->where('status', true);
        }, function ($query) {
            return $query->where('status', false);
        })
            ->get()
            ->whenNotEmpty(function ($items) {
                return $items->map(function ($item) {
                    $item->title = ucwords($item->title);
                    return $item;
                });
            });

• Apply first letter uppercase whenNotEmpty()

Conclusion

The application of Laravel when() method in Eloquent queries or collection allows you to apply conditions without using typical conditional if-else statements. This makes the code simple, particularly when filtering data, making it cleaner and more readable. You can chain multiple when() methods to handle for different conditions at a go. However, it's important to carefully review the first argument that contains custom conditions, as the callback will be executed if the condition evaluates to be true.

If you find this article useful please kindly share it with your network and feel free to use the comment section for questions, answers, and contributions.