Function Currying in Modern JavaScript: Why, When, and How

#programming #ai #javascript #coding

By: ALireza Minagar, MD, MBA, MS (Bioinformatics) Software Engineer

As software engineers, we’re always seeking ways to write more flexible, reusable code. One powerful—yet often overlooked—concept is function currying. Currying is the process of transforming a function that takes multiple arguments into a sequence of functions, each taking a single argument.
Let’s break it down, see why it’s useful, and walk through some practical JavaScript examples.

What Is Currying?
Currying transforms a function like f(a, b, c) into f(a)(b)(c). Each function takes one argument and returns another function, until all arguments are provided.

Why Use Currying?
Reusability: Easily create partially-applied functions.

Clarity: Code reads like a sequence of data transformations.

Functional programming: Currying is foundational in composing complex behavior from simple functions.

Basic Example

ES6 Arrow Functions

Currying with Lodash
Lodash provides a handy _.curry function:

Real-World Use: Event Handling

When Should You Use Currying?
When you want to create specialized functions from a generic one.

When composing functions in a pipeline.

When working with libraries or frameworks that favor functional patterns (like React hooks or Redux middleware).

Bottom Line:

Currying unlocks new patterns for clean, maintainable JavaScript. Start simple, play with partially applied functions, and soon you’ll see your code become more modular and expressive.

What are your favorite function patterns in JavaScript? Drop them in the comments!