Pluck method with fixed key

[migueliriano]

What do you think about extending Pluck to retrieve all of the values with a fixed key ?

For example in this collection, I want the name values but with a fixed key called product_name

Example code:

$collection = collect([
    ['product_id' => 'prod-100', 'name' => 'Desk'],
    ['product_id' => 'prod-200', 'name' => 'Chair'],
]);

// Current Solution:
$plucked = $collection->map(fn($collect) => ['product_id' => $collect->name]);

// Proposal solution extending `Pluck` :
$plucked = $collection->pluck(['product_name', 'name']);

// Expected output
// ['product_name' => 'Desk', 'product_name'  => 'Chair']

So the idea as you can see in the example, is extending the Pluck method of the collection to accept an array where the first index is the fixed key value product_name and the other is the column that you want to retrieve name.

[shaedrich]

Unfortunately, passing an array to the pluck method is already possible. The method then returns each column specified in the passed array. So your solution wouldn't work without introducing a breaking change and replacing existing behavior.

[migueliriano]

Thank you for this information, for some reason pluck is not working as you mentioned, when I pass an array it does not return each column, actually is returns null

Following the same example data:

$collection = collect([
		['product_id' => 'prod-100', 'name' => 'Desk'],
		['product_id' => 'prod-200', 'name' => 'Chair'],
]);
$collection->pluck(['product_id', 'name'])->toArray();

//  output
// array(2) { [0]=>  NULL  [1]=>  NULL}

Also, I don't see that usage in the Laravel 10 doc for pluck, maybe is a deprecated feature 🤔

[migueliriano]

Also, thinking more about this, we already have the second parameter called key

   public function pluck($value, $key = null)

Maybe we can extend that parameter to do one of the next options:

1. Use $key parameter as a static key if the column doesn't exist
2. If doing the first option can be risky because we are changing the behavior of that parameter, maybe we can add a third boolean parameter like fixedKey that is false by default, and if it's true that going to use the key as the fixed value instead of search another column

   public function pluck($value, $key = null, $fixedKey = false)

Examples of each point:

$collection = collect([
		['product_id' => 'prod-100', 'name' => 'Desk'],
		['product_id' => 'prod-200', 'name' => 'Chair'],
]);

// Example option 1: `product_name` doesn't exist in the collection, so going to be automatically added as fixed key
$collection->pluck('name', 'product_name')->toArray();

//Example option 2: The third `$fixedKey` is set to `true`, the second parameter will be used as a fixed key for the array result
$collection->pluck('name', 'product_name', true)->toArray();

// Same output for both points
// ['product_name' => 'Desk', 'product_name'  => 'Chair']

[shaedrich]

3. [BREAKING CHANGE] Make $key's data type a callable by default if given:

$collection->pluck('name', fn($entry) => $entry->name)->toArray(); // => Returns 'Desk' and 'Chair' as keys respectively
$collection->pluck('name', 'product_name')->toArray(); // => Returns 'product_name' as key for each entry