Currying (also partial application)

Currying.js

function person (name) {
  return function age (age) {
    return `${name} is ${age}`
  }
}

// if we called
const arg1 = 'Richard'
const arg2 = 30
console.log(person(arg1)(arg2))
// Richard is 30

////////

// We can also do
function driver (name) {
  return function age (age) {
    return function car (car) {
      return `${name} is ${age} and drives ${car}`
    }
  }
}

const drives = driver(arg1)(arg2)
console.log(drives('Toyota'))
// Richard is 30 and drives Toyota

// OR

const drives = driver(arg1)
console.log(drives(arg2)('Toyota'))
// Richard is 30 and drives Toyota
// same as above, order of passed argument will
// be carried down to the next returned function

////////

// passing two arguments in some curried functinos
function person2 (name) {
  return function age (age) {
    return function car (car, year) {
      return `${name} is ${age} and drives ${car} ${year}`
    }
  }
}

const drives = person2(arg1)(arg2)
console.log(drives('Toyota', 1997))
// Richard is 30 and drives Toyota 1997

////////

// more currying level
function person2 (name) {
  return function age (age) {
    return function car (car, year) {
      return function condition (cond) {
        return `${name} is ${age} and drives ${car} ${year} ${cond}`
      }
    }
  }
}

const condition = 'New'
const drives = person2(arg1)(arg2)
console.log(drives('Toyota', 1997)(condition))
// Richard is 30 and drives Toyota 1997 New