What’s new in the upcoming PHP 7.4?

💭 One thing I personally find missing in PHP’s typehinting, is a way to typehint array contents — e.g. “I’d like an array of Foo‘s”. As posted before (2016) you could leverage the variadic function syntax, but that only works if all arguments of the function are of the same type or if the variadic parameter is the last argument.

The addition of a [] suffix on the hinted type – like Java has – could potentially solve this all:

// ⚠️ Fictional syntax! Does not work
function workWithFoo(Foo[] $foos, string $otherArgument) : void {
    foreach ($foos as $foo) {
        // etc.
    }
}

In the mean time I resort to hackery like this (src):

// Definition
class ArrayOfFoo extends \ArrayObject {
    public function offsetSet($key, $val) {
        if ($val instanceof Foo) {
            return parent::offsetSet($key, $val);
        }
        throw new \InvalidArgumentException('Value must be a Foo');
    }
}

// Usage
function workWithFoos(ArrayOfFoo $foos, string $otherArgument) : void {
    foreach ($foos as $foo) {
        // etc.
    }
}

$foos = new ArrayOfFoo();
$foos[] = new Foo();
$foos[] = new Foo();
workWithFoos($foos, 'foo');

If anyone has a better way to tackle this, feel free to enlighten me by leaving a comment.