curry.js

function curry(func, ...argv) {
  let prevArgs = argv;
  
  function innerCurry(...args) {
    prevArgs.push(...args)

    if (prevArgs.length === func.length) {
      return func(...prevArgs);
    }
        
    return innerCurry;
  }
  
  return innerCurry;
}

function add1(a) {
  return a + 1;
}

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

function concat(a, b, c) {
  return `${a} ${b} ${c}`;
}

function hi() {
  return 'hi';
}

console.log(curry(add)(1)(4, 2)(3))

console.log(curry(concat)('a', null)()(null))

console.log(curry(hi)())