Introduction to PHP 7.4 – Features, Deprecations and Speed

PHP 7.4, released on November 28, 2019, brought significant improvements and features to the PHP language. It continued the trend of performance enhancements introduced in earlier versions, while also introducing new syntax features, deprecating outdated functionality, and offering better support for modern development practices. Here’s an overview:

Key Features of PHP 7.4

1.Typed Properties:

PHP 7.4 introduced support for type declarations on class properties. This allows developers to enforce the types of properties, providing better code safety and reducing errors.

Example:

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class User {

 public int $id;

 public string $name;

}

2. Arrow Functions:

Arrow functions (short closures) were introduced in PHP 7.4, offering a more concise syntax for writing anonymous functions. Arrow functions inherit variables from the parent scope automatically.

Example:

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$numbers = [1, 2, 3, 4];

$squared = array_map(fn($n) => $n * $n, $numbers);

3. Null Coalescing Assignment Operator (??=):

This operator provides a shorthand for assigning a value to a variable if it is null.

Example:

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$data['key'] ??= 'default_value';

4. Weak References:

PHP 7.4 introduced weak references, which allow objects to be referenced without preventing their destruction. This is useful for caching mechanisms.

Example:

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$object = new stdClass;

$weakRef = WeakReference::create($object);

5. Preloading:

Preloading allows certain files to be loaded into memory on server startup, improving performance by reducing the need to load these files during each request. This is especially beneficial for large applications.

6. Foreign Function Interface (FFI):

The FFI extension allows PHP to call C functions and access C data structures directly from userland code, opening up possibilities for more low-level operations and performance enhancements.

Deprecations in PHP 7.4

1.Curly Brace Syntax for Array Access:

The usage of curly braces for accessing array elements was deprecated in PHP 7.4. The standard square bracket syntax should be used instead.

Deprecated Example:

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$array = [1, 2, 3];

echo $array{0}; // Deprecated

Recommended:

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echo $array[0];

2. Real Type:

The real type, which was an alias for float, was deprecated. Use float instead.

3. Magic Quotes and Register Globals:

Although these features were removed in earlier versions, PHP 7.4 continued to deprecate any residual references or usage of them.

4. MBString Functions Without Explicit Encodings:

Some mbstring functions began to require an explicit encoding, with the default being deprecated. This encourages developers to always specify the encoding they intend to use.

Performance Improvements

PHP 7.4 continued the performance enhancements seen in PHP 7.0 and later versions, offering faster execution times and lower memory consumption. The preloading feature, in particular, can result in significant performance gains for applications with a large codebase by reducing the overhead of loading commonly used files during each request.

Conclusion

PHP 7.4 was a milestone release that balanced introducing new features and deprecating older, less efficient practices. Developers adopting PHP 7.4 could take advantage of improved performance, cleaner syntax, and better type safety while preparing for future versions by addressing deprecated features. Upgrading to PHP 7.4 was strongly recommended for anyone looking to maintain modern, secure, and efficient PHP applications.