1.2.1337. Use Instanceof

The instanceof operator is a more precise alternative to is_object(). It is also faster.

instanceof checks for an variable to be of a class or its parents or the interfaces it implements. Once instanceof has been used, the actual attributes available (properties, constants, methods) are known, unlike with is_object().

Last, instanceof may be upgraded to Typehint, by moving it to the method signature. instanceof and is_object() may not be always interchangeable. Consider using isset() on a known property for a simple check on objects. You may also consider is_string(), is_integer() or is_scalar(), in particular instead of !`is_object() <https://www.php.net/is_object>`_.

The instanceof operator is also faster than the is_object() functioncall.

<?php

class Foo {

    // Don't use is_object
    public function bar($o) {
        if (!is_object($o)) { return false; } // Classic argument check
        return $o->method();
    }

    // use instanceof
    public function bar($o) {
        if ($o instanceof myClass) {  // Now, we know which methods are available
            return $o->method();
        }

        return false; } // Default behavior
    }

    // use of typehinting
    // in case $o is not of the right type, exception is raised automatically
    public function bar(myClass $o) {
        return $o->method();
    }
}

?>

See also Type Operators and is_object.

1.2.1337.1. Connex PHP features

• instanceof

1.2.1337.1.1. Suggestions

• Use instanceof and remove is_object()

• Create a high level interface to check a whole family of classes, instead of testing them individually

• Use typehint when possible

• Avoid mixing scalar types and objects in the same variable

1.2.1337.1.2. Specs

Short name	Classes/UseInstanceof
Rulesets	All, Analyze, CE, CI-checks, Changed Behavior
Exakat since	0.8.4
PHP Version	All
Severity	Major
Time To Fix	Quick (30 mins)
Precision	High
Examples	TeamPass, Zencart
Available in	Entreprise Edition, Community Edition, Exakat Cloud