John Davidson

Message:

Since PHP 8.1 the native support for readonly properties arrived. But we already have constants with visibilities.

Please help me to answer these two questions:

1. Which differences are between using constants and properties?


2. When to use which one?

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My Answer:
1. Differences between using constants and properties:
- Constants are defined using the `const` keyword and are typically used for values that do not change throughout the execution of the script. They are accessed using the class name followed by `::` (scope resolution operator).
- Readonly properties, on the other hand, are defined using the `readonly` keyword and can only be assigned a value once within the class constructor. They are accessed using the object instance followed by `->` (object operator).

2. When to use which one:
- Use constants when you have values that are meant to be constant and do not change throughout the execution of the script. This can include things like configuration values, mathematical constants, or other fixed values.
- Use readonly properties when you have values that may need to be initialized once but can change during the execution of the script. This can be useful for properties that are set during object construction and should not be changed afterwards.

In general, constants are more suitable for values that are truly constant, while readonly properties are more flexible and can be used for values that may need to change under certain conditions.