A match in disguise

Let’s say we’re adding a Slack notification channel, and we go to update the method that labels each channel:

/**
 * Get channel label
 * @return string
 */
public function getLabel()
{
  $label = '';
  switch ($this->channel) {
    case 'sms': $label = 'Text Message'; break;
    case 'push': $label = 'Mobile Notification'; break;
    case 'mail': $label = 'Email'; break;
    default: $label = 'Unknown';
  }
  return $label;
}

I would call this code a little bit ugly and inefficient. But, you know, it’s been working for years. I could just add one more line and call the task done. But we’re better than that, right?

Let’s think about what a switch is conceptually. It’s flow control. Here, the only flow it’s controlling is which string gets set into a variable before returning it. But don’t we have better tools in PHP for this?

Yes we do. Let’s reach for match, because all we’re doing is matching a value to a label. Even better, we don’t need the variable now either.

public function getLabel(): string
{
  return match ($this->channel) {
    'sms' => 'Text Message',
    'push' => 'Mobile Notification',
    'mail' => 'Email',
    'slack' => 'Slack Message',
    default => 'Unknown',
  };
}

match is an expression. It’s designed to produce a value rather than run code. And that’s what this method really was all along: a value producer.