PHP Conference Nagoya 2025

ReflectionProperty::getDefaultValue

(PHP 8)

ReflectionProperty::getDefaultValueReturns the default value declared for a property

Description

public ReflectionProperty::getDefaultValue(): mixed

Gets the implicit or explicitly declared default value for a property.

Parameters

This function has no parameters.

Return Values

The default value if the property has any default value (including null). If there is no default value, then null is returned. It is not possible to differentiate between a null default value and an unitialized typed property. Use ReflectionProperty::hasDefaultValue() to detect the difference.

Examples

Example #1 ReflectionProperty::getDefaultValue() example

<?php
class Foo {
public
$bar = 1;
public ?
int $baz;
public
int $boing = 0;
public function
__construct(public string $bak = "default") { }
}

$ro = new ReflectionClass(Foo::class);
var_dump($ro->getProperty('bar')->getDefaultValue());
var_dump($ro->getProperty('baz')->getDefaultValue());
var_dump($ro->getProperty('boing')->getDefaultValue());
var_dump($ro->getProperty('bak')->getDefaultValue());
?>

The above example will output:

int(1)
NULL
int(0)
NULL

See Also

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User Contributed Notes 1 note

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10
rwalker dot php at gmail dot com
3 years ago
An equivalent for PHP 7:

<?php
$reflectionProperty
= new \ReflectionProperty(Foo::class, 'bar');

//PHP 8:
$defaultValue = $reflectionProperty->getDefaultValue();

//PHP 7:
$defaultValue = $reflectionProperty->getDeclaringClass()->getDefaultProperties()['bar'] ?? null;
?>
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