fundamental abstractions, setters, getters, iterators

abstractions.js

// Abstraction
// Function
const x = (x) => x * x
// getter
const getter = () => 1
    // example
const getObject = () => ({
  name: 'abiodun'
})

// setter 
const setter = (x) => {

}
// example
console.log(x)

// getter getter

const getterGetter = () => (() => 1)
// example 
function getterContinued() {
  let i = 1;
  return function() {
    i = i+1
    return i
  }
}

let confirmGetter = getterContinued()
console.log(confirmGetter(), 'what do we have')
console.log(confirmGetter(), 'what do we have')
console.log(confirmGetter(), 'what do we have')
console.log(confirmGetter(), 'what do we have')
// reset

confirmGetter = getterContinued()
console.log(confirmGetter(), 'what do we have')
console.log(confirmGetter(), 'what do we have')
console.log(confirmGetter(), 'what do we have')
console.log(confirmGetter(), 'what do we have')

// setter setter
const setterSetter = (cb) => {

}
// example callbacks
const exampleSetSetter = (cb) => {
  cb('yooo');
}
exampleSetSetter(console.log)

// iterables
const iterables  = () => (() => ({value: 1, done: true}))

// examples

const exampleIterable = () => {
  let i = 0;
  return function() {
  if(i< 50) {
    i=i+1
    return {
      value: i,
      done: false
    }
  }
  return {
    value: i,
    done: true
  }
}
}
const iterable = exampleIterable()
// for(let result = iterable(); !result.done; result = iterable()) {
//   console.log(result.value)
// }

// using es6 built in iterator
const sampleIterator = {
  [Symbol.iterator]: () => {
    let i = 0;
      return {
        next: () => {
        if(i< 50) {
          i=i+1
          return {
            value: i,
            done: false
          }
        }
        return {
          value: i,
          done: true
        }
      }
    }
}
}
const getIterator = sampleIterator[Symbol.iterator]()

for(let result = getIterator.next(); !result.done; result = getIterator.next()) {
  console.log(result.value)
}
// equivalently

for(let x of sampleIterator) {
  console.log(x, 'this is a let of')
}

// with generator functions syntatic suger
function* upTo50() {
  let i = 0 
  while(true) {
    if (i < 50) {
      yield i
      i = i+1
    }
    else {
      return
    }
  }
}
const countUpto50 = upTo50()
for(let result = countUpto50.next(); !result.done; result = countUpto50.next()) {
  console.log(result.value, 'with generator')
}

// then former definition of promises and observables