lubien

const add = (x, y) => x + y
const sub = (x, y) => x - y

console.log('10 + 3 - 4 =', sub( add(10, 3), 4 ) )

lubien

const add = x => y => x + y
const sub = x => y => x - y

console.log('10 + 3 - 4 =', sub( add(10)(3) )(4) )

lubien

// if the other argument is lower than 0, return 0
const atLeastZero = Math.max.bind(null, 0)

console.log(atLeastZero(10))  // 10
console.log(atLeastZero(-10)) // 0
console.log(atLeastZero(0))   // 0

lubien

const curry = fn =>
  // if this function takes one argument
  fn.length === 1
    // it's already curry
    ? fn 
    // otherwise let's create a curry version
    // return a function that takes one argument
    // when we receive it we bind it to fn to create a new
    // function then we curry the rest recursively
    : x => curry(fn.bind(null, x))

lubien

const maxCurry = x => y =>
  Math.max(x, y)
  
// if the other argument is lower than 0, return 0
const atLeastZero = maxCurry(0)

console.log(atLeastZero(10))  // 10
console.log(atLeastZero(-10)) // 0
console.log(atLeastZero(0))   // 0

lubien

const letterToMessage = (letter, index) =>
  `${letter} is at position ${index}`
  
const letterIsAlwaysZ = letterToMessage.bind(null, 'z')
  
const letters = ['a', 'b', 'c', 'd', 'e']
const messages = letters.map(letterToMessage)

// Using the full function
console.log(letterToMessage('a', 0)) // a is at position 0

lubien

const partial = (fn, ...args) =>
  fn.bind(null, ...args)

const propEq = (propName, expectedValue, object) =>
  object[propName] === expectedValue

const users =
[ {username: 'lubien',       online: false}
, {username: 'rian-vergara', online: true }
, {username: 'leochrisis',   online: true }

lubien

const partial = (fn, ...args) =>
  fn.bind(null, ...args)

const prop = (propName, object) =>
  object[propName]  

const users =
[ {username: 'lubien',       name: 'João'    }
, {username: 'rian-vergara', name: 'Rian'    }
, {username: 'leochrisis',   name: 'Leonardo'}

lubien

const getAll = userUID =>
	database
	.ref('user_data')
	.child(userUID)
	.child('customers')

// exemplo de uso:

getAll(myUserId).on('value', snap => {
	const value = snap.val()

lubien

const partial = (fn, ...args) =>
  fn.bind(null, ...args)

const add3 = (x, y, z) => x + y + z
const addOnePlusTwo = partial(add3, 1, 2)

console.log(addOnePlusTwo(1))  // 4
console.log(addOnePlusTwo(10)) // 13