PHP 8 News: Nullsafe Operator
Tags: php
Published: 2024-02-10 00:09:26

The Nullsafe Operator, introduced in PHP `8.0`, is a feature that simplifies the handling of **null** values in chains of method or property calls.

### Nullsafe Operator (?->)

**Purpose:**

The **Nullsafe Operator** is designed to streamline the process of working with **nullable** values, particularly in scenarios where you have a chain of method or property calls, and any one of them might return a **null** value.

**Syntax:**

The syntax of the **Nullsafe Operator** is as follows:

```php
$variable?->propertyOrMethod()
```

Here, `$variable` is the variable that may be **null**, and `propertyOrMethod` is the property or method you want to access if `$variable` is not **null**.

**Example:**

Consider the following example without the **nullsafe operator**:

```php
if ($object !== null) {
    $result = $object->getProperty();
    if ($result !== null) {
        $finalResult = $result->doSomething();
    }
}
```

With the **nullsafe operator**, this can be simplified:

```php
$finalResult = $object?->getProperty()?->doSomething();
```

**How it Works:**

- If `$object` is not **null**, the property access or method call proceeds.

- If at any point in the chain a **null** value is encountered, the entire expression evaluates to **null**, and further method or property calls are skipped.

**Chaining Methods and Properties:**

You can chain multiple method or property calls using the **nullsafe operator**, making the code more concise:

```php
$value = $object?->getProperty()?->method1()?->method2()->property;
```

In this example, if any part of the chain returns **null**, the entire expression will be **null**.

**Error Suppression:**

It's important to note that the **nullsafe operator** does not **suppress errors**. If a method or property does not exist, a **fatal error** will still be **triggered**. However, if a **null** value is encountered, the expression gracefully evaluates to **null** without causing an **error**.

### Short-Circuiting

The concept of **short-circuiting** in the context of the **Nullsafe Operator** in `PHP` refers to the early interruption of the execution of a chain of method or property calls as soon as a **null** value is encountered. This means that if a point in the chain returns a **null** value, subsequent calls are automatically skipped, and the result of the expression is immediately set to **null**.

Suppose you have a chain of method or property calls using the **Nullsafe Operator**, as in the following example:

```php
$result = $object?->getProperty()?->method1()?->method2()->anotherProperty;
```

In this example, if at any point in the chain a **null** value is encountered:

1. `$object` **is null**: Execution stops there, and `$result` is immediately set to **null**. None of the subsequent calls (`getProperty()`, `method1()`, `method2()`, `anotherProperty`) are evaluated.

2. `getProperty()` **returns null**: Execution stops, and $result is set to **null**. Subsequent calls (`method1()`, `method2()`, `anotherProperty`) are not evaluated.

3. `method1()` **returns null**: Execution stops, and $result is set to **null**. Subsequent calls (`method2()`, `anotherProperty`) are not evaluated.

4. `method2()` **returns null**: Execution stops, and $result is set to **null**. The subsequent call (`anotherProperty`) is not evaluated.

5. `anotherProperty` **is null**: Execution stops, and `$result` is set to null.

This behavior is known as **short-circuiting** because as soon as a **null** value is encountered at any point in the expression, there is no need to evaluate the remaining method or property calls since the final result will be **null** anyway. This can make the code more efficient and concise, especially in situations where you need to avoid unnecessary evaluations in chains of methods or properties.