Unpack Arrays with Spread Syntax in PHP 8.1

Use array unpacking (...) inside square bracket array literals for string-keyed and indexed array merging.

PHP 8.1 expanded array unpacking to support string keys inside square bracket array literals, replacing verbose array_merge() calls with clean spread syntax.

Code Example

$defaults = [
    'theme'         => 'dark',
    'notifications' => true,
];

$userCustom = [
    'notifications' => false,
    'language'      => 'en',
];

// Unpacks and merges arrays natively (later values overwrite earlier keys)
$options = [...$defaults, ...$userCustom];

// Result:
// [
//     'theme'         => 'dark',
//     'notifications' => false,
//     'language'      => 'en',
// ]

Key Benefits

• Clean Syntax: Replaces verbose array_merge() function calls with native spread operator syntax.
• String Key Support: In PHP 8.1+, string keys are fully supported; conflicting keys are overwritten by later elements in the list.
• Array Composition: Ideal for merging configuration defaults, request payloads, and query parameters cleanly.