Laravel集合中的when方法

发表于
Hope is a good thing and maybe the best of things. And no good thing ever dies.

Starting at v5.4.12, Laravel Collections now includes a when method that allows you to perform conditional actions on the items without breaking the chain.

Like all the other Laravel Collection methods this one can have a lot of use cases but one example that comes to mind is being able to filter based on a query string parameter.

To demonstrate that example, let’s pretend we have a list of hosts from the Laravel News Podcast:

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$hosts = [
    ['name' => 'Eric Barnes', 'location' => 'USA', 'is_active' => 0],
    ['name' => 'Jack Fruh', 'location' => 'USA', 'is_active' => 0],
    ['name' => 'Jacob Bennett', 'location' => 'USA', 'is_active' => 1],
    ['name' => 'Michael Dyrynda', 'location' => 'AU', 'is_active' => 1],
];

Previously to filter based on a query string you might do something like this:

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$inUsa = collect($hosts)->where('location', 'USA');

if (request('retired')) {
    $inUsa = $inUsa->filter(function($employee){
        return ! $employee['is_active'];
    });
}

With the new when method you can now do this all in one Collection chain:

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$inUsa = collect($hosts)
    ->where('location', 'USA')
    ->when(request('retired'), function($collection) {
        return $collection->reject(function($employee){
            return $employee['is_active'];
        });
    });

https://laravel-news.com/laravel-collections-when-method