PHP 7.4 – Null coalescing assignment operator

A lot of updates have come in PHP 7.4. One of them is null Coalesce Assignment Operator?? (=). This is used in combination with isset() method to replace the null Coalesce operation. This operator is used for assigning its right-hand operand value to its left-hand operand only if the left-hand operand value is null.this update you can speed up work.


// Equivalent code using ternary operator
   $username = isset($_GET['username']) ? $_GET['username'] : 'not body';
   echo $username;

// Chaining ?? operation
    $username = $_GET['username'] ?? $_POST['username'] ?? 'not body';
    echo  $username;

The Null Coalesce Assignment Operator(??=) can now further simplify the above sentence as follows:


$_GET['username'] ??= 'no body';

Difference between Null Coalescing Operator and Ternary Operator

Ternary Operator remains associative where as, Null Coalescing Operator is associative to the right.
If left operand is null, Ternary Operator throws e-notice, while null coalescing operator does not throw e-notice if left operand does not exist.
Ternary Operator checks if the value is valid even if the value is not null, the Null coalescing operator checks.
If more iteration is needed to be done, the null coalescing operator found to be quicker than the ternary operator.
Null coalescing operator offers comparatively improved readability as well.

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Difference between Null Coalescing Operator and Ternary Operator