Solidity Tutorial: all about Modifiers
In Solidity, Modifiers express what actions are occurring in a declarative and readable manner. They are similar to the decorator pattern used in Object Oriented Programming.
What is exactly a Modifier in Solidity ?
The Solidity documentation define a modifier as follow:
A function modifier is a compile-time source code roll-up.
It can be used to amend the semantics of functions in a declarative way.
From this definition, we can understand that a modifier aims to change the behaviour of the function to which it is attached.
For instance, automatically checking a condition prior to executing the function (this is mainly what they are used for).
Modifiers are useful because they reduce code redundancy. You can re-use the same modifier in multiple functions if you are checking for the same condition over your smart contract.
When to use a modifier in Solidity?
The main use case of modifiers is for automatically checking a condition, prior to executing a function. If the function does not meet the modifier requirement, an exception is thrown…
