PHP | JsonSerializable jsonSerialize() Function

PHP's JsonSerializable interface provides a convenient way to customize JSON serialization for an object. The interface has only one method - jsonSerialize() - which should return data that can be serialized to JSON.

Syntax

jsonSerialize(): mixed

Return Value

The jsonSerialize() function returns data that can be serialized to JSON. The return type can be any value that is natively serializable to JSON, such as an array or an object.

Example Usage

Consider the following example, where we have a class named Car that implements the JsonSerializable interface.

class Car implements JsonSerializable {
    private $make;
    private $model;
    private $year;

    public function __construct(string $make, string $model, int $year) {
        $this->make = $make;
        $this->model = $model;
        $this->year = $year;
    }

    public function jsonSerialize() {
        return [
            'make' => $this->make,
            'model' => $this->model,
            'year' => $this->year
        ];
    }
}

In the above code, we have defined a Car class that has three properties - $make, $model, and $year. This class also implements the JsonSerializable interface and provides a custom implementation of the jsonSerialize() method.

Now let's create an instance of the Car class and encode it to JSON using the json_encode() function.

$car = new Car('BMW', 'X5', 2021);
$json = json_encode($car);
echo $json;

The output of the above code will be as follows:

{"make":"BMW","model":"X5","year":2021}

Here we can see that the jsonSerialize() method of the Car class was used to customize the JSON serialization of the object.

Conclusion

In conclusion, the JsonSerializable interface in PHP provides a convenient way to customize JSON serialization for an object. The jsonSerialize() method should return data that can be natively serialized to JSON, such as an array or an object. This allows developers to easily customize the JSON output of their PHP applications.