Two arguments of the same type. Two equal names

TL;DR: Turn on Strict Checks

Problems

Unexpected errors
Ambiguity
The Least Surprise Principle violation
Portability

Solutions

Enable strict mode
Use role-naming arguments

Context

Most compilers forbid duplicate parameters since they are a common mistake in a large parameters list

Sample Code

Wrong

function addNumbers(a, b, a) {
  console.log(a + b);
}

addNumbers(2, 3, 4);

// Outputs 7 (2 + 3 + 2)

Right

"use strict";

function addNumbers(a, b, a) { }
//                          ^
// SyntaxError: Duplicate parameter name not allowed in this context

Detection

[X] Automatic

By enabling strict mode, the compiler will warn us

Conclusion

Enable the stricter modes you can find on your compilers.

Try to fail fast and catch errors as early as possible and leave the hard and dumb work to the tools.

Relations

Code Smell 188 - Redundant Parameter Names

Maxi Contieri ・ Dec 24 '22

#webdev #beginners #programming #tutorial

Code Smell 65 - Variables Named After Types

Maxi Contieri ・ Apr 2 '21

#codenewbie #codesmells #oop #webdev

More Info

Sonar Source

Mozilla Org

Fail Fast

Maxi Contieri ・ Dec 6 '20

#codenewbie #programming #webdev #oop

Disclaimer

Code Smells are my opinion.

Credits

Photo by Caroline Veronez on Unsplash

One of the things I've been trying to do is look for simpler or rules underpinning good or bad design. I think one of the most valuable rules is avoiding duplication. "Once and only once" is the Extreme Programming phrase.

Martin Fowler

Software Engineering Great Quotes

Maxi Contieri ・ Dec 28 '20

#codenewbie #programming #quotes #software

This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code

Maxi Contieri ・ May 21 '21

#codenewbie #tutorial #codequality #beginners

Code Smell 214 - Duplicate Parameter Names