Simple and small wrapper to allow for partial function invocation from left to right

partial-left.js

/**
 * Make a function partially invokable from left to right.
 *
 * @example
 * let addThreeNumbers  = partialLeft((a, b, c) => a + b + c);
 * addThreeNumbers(1)(2)(3); // => 6
 * addThreeNumbers(1, 2)(3); // => 6
 * addThreeNumbers(1)(2, 3); // => 6
 * addThreeNumbers(1, 2, 3); // => 6
 *
 * @param {Function} fn The function to make partially invokable.
 * @return {Function} A partially invokable function.
 * @license The-Unlicense
 */
function partialLeft(fn) {
  // Check if the provided argument is a function
  if (typeof fn !== 'function') throw Error('partialLeft should be provided with a function');

  // Get the arity of the function
  let arity = fn.length;

  // Return the return value of resolver() which is a partially invokable function
  return (function resolver() {
    // Create *local* memory to allow for reuse of the partially invokable function
    let memory = Array.from(arguments);

    // Return the partally invoked function
    return function() {
      // Get the arguments from this call and combine them with the memory
      let args = Array.from(arguments);
      args = memory.concat(args);

      // Call fn if enough arguments have been provided, otherwise return
      // another partially invoked function
      let next = args.length >= arity ? fn : resolver;
      return next.apply(null, args);
    };
  }());
};