temp.js

/*
given an array of numbers, 
return a new array in which each number is doubled
*/

function map(array, instruction) {
  let newArr = []
  for (let item of array) {
    newArr.push(instruction(item))
  }
  return newArr
}

const double = item => item * 2

const result = map([1,2,3,4], double)

/*
given an array of objects,
pluck a specific property from each
*/

function pluck(array, propName) {
  let newArr = []
  for (let item of array) {
    if (item.hasOwnProperty(propName)) {
      newArr.push(item[propName])
    }
  }
  return newArr
}

const profiles = [
  {
    address: 'Jakarta',
  },
  {
    name: 'Hafidz',
    age: 22,
  },
  {
    name: 'Ilham',
    age: 50,
  },
  {
    name: 'Aji',
    age: 10,
  }
]

const result1 = pluck(profiles, 'names')
const result2 = pluck(profiles, 'name')
const result3 = pluck(profiles, 'address')
const result4 = pluck(profiles, 'age')

/*
compare two values, shallow comparing content in arrays
*/

function shallowCompare(array1, array2) {
  let result = true
  if (array1.length != array2.length) {
    result = false
  } else {
    for (let i = 0; i < array1.length; i++) {
      if (array1[i] !== array2[i]) {
        result = false
      }
    }
  }
  return result
}

const result1 = shallowCompare([1,2,3], [1,2,3])
const result2 = shallowCompare([1,2,3], [6,2])
const result3 = shallowCompare([1,2,3], [1,2,3,4])