Currying.js

/* Adopted from an example provided by Ezekiel Lawson at LogRocket. Goal was to better understand the flow of Currying functions and bind().

https://blog.logrocket.com/understanding-javascript-currying/
*/

// new function called curry which takes a function as an argument. In this case, the totalNum function is passed and it expects 3 arguments
const curry = (fn) => {
// returns a function called curried which takes the args and spreads them ...
  return curried = (...args) => {
    console.log("fn length: " + fn.length);
    console.log("args length: " + args.length);
    console.log(`args: `,...args);
    // compare the number of expected arguments in the passed function "fn" to the number passed in the function "curried"
    if (fn.length !== args.length) {
    	console.log(`fn and args lengths not matching. passing: `,...args);
      return curried.bind(null, ...args)
    }
    //recurse
    // this ultimately passes the desired number of arguments to totalNu
    console.log("recursing");
    return fn(...args);
  };
}
const totalNum = (x, y, z) => {
	console.log("in totalNum");
  return x + y + z
}
const curriedTotal = curry(totalNum);



console.log(curriedTotal(10)(20)(30));
console.log(curriedTotal(1,2,3,4,5));