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Can you pass variables into a Class in PHP?

I'm working through a tutorial on Node where I've got an MCV architecture going on.

This is the relevant piece of my Controller:

const Product = require("../models/product");

exports.postAddProduct = (req, res, next) => {
  const product = new Product(req.body.title); // right here I'm establishing a new instance of my Product class and I'm passing a variable into that class that's coming from my form
  product.save();
  res.redirect("/");
};

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This is the relevant portion of my Model:

const products = [];

module.exports = class Product {
  constructor(title) {
    this.title = title;
  }

  save() {
    products.push(this);
  }

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What you see works and there's nothing about it that's especially confusing, but I did have a question.

When I saw this syntax, I was able to understand its logic based on my experience with PHP, as far as creating an instance of a class and having a constructor sitting at the top of that class.

All good.

But that I started looking at it a little bit closer and noticed that I was passing a variable into a class.

You don't do that with PHP do you?

I know that's a bizarre question, but when I think of constructors in PHP, I'm thinking of defining some properties and the attaching values to those properties that I can then access throughout my class depending on their visibility.

But do you / can you pass variables into a class in PHP?

There you go! A random question to kick off your Thursday morning...

gr8gonzo

Absolutely you can. Here's a code example showing a variety of ways of passing in variables, some in constructors, some with defaults, etc...

<?php
class MyClass
{
  private $instanceNumber;
  private static $instanceCounter = 0;
  
  private $fav_color;
  private $favorite_food;
  private $locker_combo;
  public $other_notes;

  public function __construct($favorite_color, $favorite_food, $locker_combination = 123)
  {
    $this->instanceNumber = ++self::$instanceCounter;
    
    $this->fav_color = $favorite_color;
    $this->favorite_food = $favorite_food;
    $this->locker_combo = $locker_combination;
  }

  public function DisplayStuff()
  {
    echo "MyClass #" . $this->instanceNumber . ":\n";
    echo "  Favorite Color: " . $this->fav_color . "\n";
    echo "  Favorite Food: " . $this->favorite_food . "\n";
    echo "  Locker Combination: " . $this->locker_combo . "\n";
    echo "  Other Notes: " . $this->other_notes . "\n";
    echo "\n";
  }
}

$MC1 = new MyClass("Green", "Watermelon");
$MC1->DisplayStuff();

$MC2 = new MyClass("Red", "Apple", 12345);
$MC2->DisplayStuff();

$MC3 = new MyClass("Orange", "Orange", 54321);
$MC3->other_notes = "ORANGES!";
$MC3->DisplayStuff();

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Output:

MyClass #1:
  Favorite Color: Green
  Favorite Food: Watermelon
  Locker Combination: 123
  Other Notes: 

MyClass #2:
  Favorite Color: Red
  Favorite Food: Apple
  Locker Combination: 12345
  Other Notes: 

MyClass #3:
  Favorite Color: Orange
  Favorite Food: Orange
  Locker Combination: 54321
  Other Notes: ORANGES!

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Bruce Gust

ASKER

OK, Gonzo! I get that, but could you do something like this:

$MC1 = new MyClass($color, $fruit);
$MC1->DisplayStuff();

ASKER CERTIFIED SOLUTION

gr8gonzo

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