WordPress at a glance
function is not described

Services_JSON::isError() public WP 1.0

Deprecated in from version 5.3.0. It is no longer supported and can be removed in future releases. Use PHP native JSON extension instead.

{} It's a method of the class: Services_JSON{}

No Hooks.

Return

Null. Nothing.

Usage

$Services_JSON = new Services_JSON();
$Services_JSON->isError( $data, $code );

Changelog

Deprecated Since 5.3.0 Use the PHP native JSON extension instead.

Code of Services_JSON::isError() WP 5.5.1

<?php
function isError($data, $code = null)
{
    _deprecated_function( __METHOD__, '5.3.0', 'The PHP native JSON extension' );

    if (class_exists('pear')) {
        return PEAR::isError($data, $code);
    } elseif (is_object($data) && (get_class($data) == 'services_json_error' ||
                             is_subclass_of($data, 'services_json_error'))) {
        return true;
    }

    return false;
}