Code Smell 116 — Variables Declared With ‘var’
Var, Let, Const: are all the same, aren’t they?
TL;DR: Choose wisely your variable names, scope, and mutability.
Problems
- Mutability
- Readability
Solutions
1. Declare const all variables unless you need to change them
Context
Most languages don’t need variable declarations.
Some other languages allow us to state mutability.
We should be strict and explicit with our declarations.
Sample Code
Wrong
Right
Detection
[X] Manual
With mutation testing by forcing a ‘const’ declaration, we can check if a value remains constant and be more declarative by explicitly enforcing it.
Tags
- Mutability
- Javascript
Conclusion
Readability is always very important.
We need to explicitly state our intentions and usages.
Relations
More Info
Just as it is a good practice to make all fields private unless they need greater visibility, it is a good practice to make all fields final unless they need to be mutable.
Brian Goetz
This article is part of the CodeSmell Series.
