JavaScript currying function

function add(x) {
  return function(y) {
    return x + y;
  };
}

let add5 = add(5);
console.log(add5(3)); // Output: 8

More complex curry function

function curry(func) {
  return function curried(...args) {
    if (args.length >= func.length) {
      return func.apply(this, args);
    } else {
      return function(...moreArgs) {
        return curried.apply(this, args.concat(moreArgs));
      };
    }
  };
}

function add(a, b, c) {
  return a + b + c;
}

const curriedAdd = curry(add);

console.log(curriedAdd(1)(2)(3)); // Outputs: 6
console.log(curriedAdd(1, 2)(3)); // Outputs: 6
console.log(curriedAdd(1)(2, 3)); // Outputs: 6
console.log(curriedAdd(1, 2, 3)); // Outputs: 6