composition-example-4.js

//helper function

const assignFuncs = (state, funcs) => funcs
  .map((func) => ({[func.name]: (...args) => func(state, ...args)}))
  .reduce((acc, func) => ({...acc, ...func}))

//example

const bark = (state, howManyTimes) => {
  state.barks += howManyTimes
}

const eat = (state, howMuch) => {
  state.food -= howMuch
}

const dog = (name) => {
  const state = {
    name,
    barks: 0,
    food: 100,
  }
  return Object.assign(state, {
    ...assignFuncs(state, [bark, eat]),
  })
}

const alfie = dog('Alfie')
alfie.bark(3)
alfie.eat(6)
console.log(alfie.barks) //3
console.log(alfie.food) //94