function.chaining() vs currying()()()()()

JavaScript offers a rich set of functional programming features that help developers write cleaner, more expressive, and modular code. Two such concepts are function chaining and currying. While both promote composability, they differ in syntax, design patterns, and use cases.

🔗 What is Function Chaining?

Function chaining is a technique where multiple methods are called on the same object in a single line of code. Each method returns the object itself (or something chainable), allowing further calls to be made.

📦 Use Case: Fluent APIs

Libraries like jQuery, Lodash, and Moment.js utilize chaining to provide fluent, readable APIs.

✅ Example: A Simple Calculator function

✅ When to Use Function Chaining

When designing stateful APIs.
When the same object or context is being modified or reused.
To write more readable and expressive code for method sequences.

🥘 What is Currying?

Currying is a functional programming technique where a function with multiple arguments is transformed into a sequence of functions, each taking a single argument.

📦 Use Case: Reusability and Partial Application

Currying is especially useful when you want to fix some arguments of a function and reuse it in multiple contexts.

✅ Example 1:

✅ Example 2: Infinite currying

Infinite currying allows you to keep calling the function simply by returning the function itself until you decide to stop.

✅ When to Use Currying

When you need to preload some parameters.
To create higher-order or partially applied functions.
In function composition for functional programming patterns.