JavaScript: Uncurry a function up to depth n

JavaScript fundamental (ES6 Syntax): Exercise-114 with Solution

Write a JavaScript program to uncurry a function up to depth n.

• Return a variadic function.
• Use Array.prototype.reduce() on the provided arguments to call each subsequent curry level of the function.
• If the length of the provided arguments is less than n throw an error.
• Otherwise, call fn with the proper amount of arguments, using Array.prototype.slice(0, n).
• Omit the second argument, n, to uncurry up to depth 1.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2

// Define the 'uncurry' function.
const uncurry = (fn, n = 1) => (...args) => {
  // Define a helper function 'next' that applies functions sequentially.
  const next = acc => args => args.reduce((x, y) => x(y), acc);
  // Check if the number of arguments is sufficient.
  if (n > args.length) throw new RangeError('Arguments too few!');
  // Apply 'fn' partially with the first 'n' arguments and return the resulting function.
  return next(fn)(args.slice(0, n));
};

// Define a curried addition function.
const add = x => y => z => x + y + z;
// Uncurry the 'add' function to accept three arguments.
const uncurriedAdd = uncurry(add, 3);
// Test the uncurried addition function with three arguments.
console.log(uncurriedAdd(1, 2, 3));
// Output: 6

Output:

6

Visual Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-114-1 by w3resource (@w3resource) on CodePen.

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