What is the currying function

Currying is the process of transforming a function with multiple arguments into a sequence of nested functions, each accepting only one argument at a time.

This concept is named after mathematician Haskell Curry, and is commonly used in functional programming to enhance modularity and reuse.

Before Currying (Normal n-ary Function)

const multiArgFunction = (a, b, c) => a + b + c;

console.log(multiArgFunction(1, 2, 3)); // Output: 6

This is a standard function that takes three arguments at once.

After Currying (Unary Function Chain)

const curryUnaryFunction = (a) => (b) => (c) => a + b + c;

console.log(curryUnaryFunction(1));       // Returns: function (b) => ...
console.log(curryUnaryFunction(1)(2));    // Returns: function (c) => ...
console.log(curryUnaryFunction(1)(2)(3)); // Output: 6

Each function in the chain accepts one argument and returns the next function, until all arguments are provided and the final result is computed.

Benefits of Currying

• Improves code reusability → You can partially apply functions with known arguments.

• Enhances functional composition → Easier to compose small, pure functions.

• Encourages clean, modular code → You can split logic into smaller single-responsibility functions.