Question

To create an empty JSON object I do usually use:

json_encode((object) null);

casting null to an object works, but is there any other preferable way and/or any problem with this solution?

Answer 1

Recommended method

json_decode ("{}") will return a stdClass per default, using the below should therefor be considered safe/portable and correct.

json_encode (new stdClass);

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Your solution could work..

The documentation specifies that (object) null will result in an empty object, some might therefor say that your code is valid and that it’s the method to use.

PHP: Objects – Manual

If a value of any other type is converted to an object, a new instance of the stdClass built-in class is created. If the value was NULL, the new instance will be empty.

.. but, try to keep it safe!

Though you never know when/if the above will change, so if you’d like to be 100% certain that you will always will end up with a {} in your encoded data you could use a hack such as:

$empty = json_decode ("{}");
$result = json_encode($empty); // "{}"

Even though it’s tedious and ugly I do assume/hope that json_encode/json_decode is compatible with one another and always will evaluate the following to true:

$a = <something>;

$a === json_decode (json_encode ($a));