PHP › JSON Handling in PHP
How do you properly handle errors when parsing potentially invalid JSON, and how does the JSON_THROW_ON_ERROR flag simplify this compared to manually checking json_last_error?
IntermediateAnswer
By default, json_decode returns null if it encounters invalid JSON, but null is also a valid JSON value itself, making it ambiguous whether decoding actually failed or the JSON genuinely contained a null value, which historically required manually checking json_last_error afterward, while passing the JSON_THROW_ON_ERROR flag instead causes json_decode to throw a proper catchable JsonException on failure, letting you handle invalid JSON using a standard try catch block instead of manually checking an error code after every single call.
try {
$data = json_decode($jsonString, true, flags: JSON_THROW_ON_ERROR);
} catch (JsonException $e) {
echo 'Invalid JSON received: ' . $e->getMessage();
}Real-world example An API integration script switches from manually checking json_last_error after every decode call to using the JSON_THROW_ON_ERROR flag, significantly simplifying its error handling code with a single consistent try catch block.