function fixed (f) { const me = this return function next (...a) { if (a.length < f.length) { return function (...b) { return next(...a, ...b) } } return f.call(me, ...a) } } export default fixed

This code implements a currying function for the function f.

How it works:

• It returns a function next that collects arguments.
• If fewer arguments are passed than f expects (according to f.length), it returns a new function that accepts the remaining arguments.
• When the number of arguments reaches the required amount, the original function f is called with the collected arguments.

Example of usage:

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

const curriedSum = fixed(sum);

console.log(curriedSum(1)(2)(3)); // 6
console.log(curriedSum(1, 2)(3)); // 6
console.log(curriedSum(1)(2, 3)); // 6

Thus, fixed allows calling a function with partial application of arguments, which is convenient for functional programming.