JavaScript: Curry (curries) a function

JavaScript fundamental (ES6 Syntax): Exercise-46 with Solution

Curry a Function

Write a JavaScript program to curry (curries) a function

According to wiki.haskell.org "Currying is the process of transforming a function that takes multiple arguments into a function that takes just a single argument and returns another function if any arguments are still needed. f x y = g (x,y), however the curried form is usually more convenient because it allows partial application.

Note: Use recursion. If the number of provided arguments (args) is sufficient, call the passed function fn. Otherwise, return a curried function fn that expects the rest of the arguments. If you want to curry a function that accepts a variable number of arguments (a variadic function, e.g. Math.min()), you can optionally pass the number of arguments to the second parameter arity.

• Use recursion.
• If the number of provided arguments (args) is sufficient, call the passed function fn.
• Otherwise, use Function.prototype.bind() to return a curried function fn that expects the rest of the arguments.
• If you want to curry a function that accepts a variable number of arguments (a variadic function, e.g. Math.min()), you can optionally pass the number of arguments to the second parameter arity.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2
// Define a function 'curry' that takes a function 'fn', an arity 'arity', and optional arguments 'args'.
const curry = (fn, arity = fn.length, ...args) =>
  // Check if the number of provided arguments is sufficient to invoke the function.
  arity <= args.length ? fn(...args) : curry.bind(null, fn, arity, ...args);

// Test the 'curry' function with Math.pow and Math.min functions, and log the results.
console.log(curry(Math.pow)(2)(8)); // Output: 256
console.log(curry(Math.min, 3)(10)(50)(2)); // Output: 2

Output:

256
2

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-1-46 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that transforms a multi-argument function into a curried function that can be partially applied.
• Write a JavaScript function that curries another function, allowing it to accept arguments one at a time.
• Write a JavaScript program that demonstrates currying by converting a function with three parameters into nested unary functions.

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