Long Parameter List

A function with too many arguments.

“The ideal number of arguments for a function is zero (niladic). Next comes one (monadic), followed closely by two (dyadic). Three arguments (triadic) should be avoided where possible.” – Robert C. Martin

Signs of Use (Symptoms)

Function takes more than 3 arguments.
Arguments are added to an existing function as requirements grow.
Many boolean “flag” arguments.

Why it is bad (Consequences)

Readability: Hard to remember argument order.
Error Prone: Easy to swap arguments of the same type.
Testability: Requires many permutations of inputs.

Why it happens (Root Cause)

Adding a parameter is faster than refactoring to use an options object or breaking the function.

When it might be okay (Exceptions)

Well-known standard APIs (e.g., Math.pow(x, y)).

Explanation

Problem

A function started with 2 parameters. Ticket by ticket, it grew to 8.

The Flaw

Cognitive overload. You must remember the meaning and order of each argument.

Real world analogy

A form with 50 fields on one page. Break it into sections/tabs.

Refactoring Solution

Introduce Parameter Object: Group related params into an object.
Preserve Whole Object: Pass an object that already holds the data.

Pros and Cons (of the Antipattern)

Pros (Why people do it)	Cons (The price you pay)
Explicit	Hard to read Easy to make mistakes