Defining Constants
In Dart, constants are defined using the keywords final and const, which ensure that certain variable values remain unchanged throughout the program's execution. A final variable can be assigned once and its value can be determined at runtime, while a const variable must be assigned a value known at compile-time. This distinction is crucial; for example, DateTime.now() cannot be used with const since it requires runtime execution. A practical guideline is to use const for fixed values and final for values that are determined during program execution but should not be reassigned.
Overview
Sometimes we create a variable and assign it a very specific value with the intention of never changing the value. For the program to run successfully, it is of the utmost importance that the value of the variable remains the same throughout its lifetime. To create such a variable, the keywords final and const should be used. Before we get into what final and const actually do, we need to learn the difference between compile-time and runtime ...