Promisify Node async functions dynamically. (curries when provided no additional arguments)

promisify.js

function promisify(func, ...args) {
  if (arguments.length === 1) {
    // Curry with the decremented arity
    return promisify.bind(null, func)
  }

  return new Promise((resolve, reject) => {
    func(...args, (error, ...cbArgs) => {
      if (error) {
        return reject(error)
      }
      resolve(cbArgs)
    })
  })
}