05-31-19.js

// Arrays

// Create an array of numbers, 1 through 10

nums = [1,2,3,4,5,6,7,8,9,10]

// Write a function, called forLoop that takes an array as a parameter, runs the array through a for(...) loop and does a console.log() of each element.

function forLoop(arr) {
  for(let i=0; i<arr.length; i++){
    console.log(arr[i])
  }
}

// Write a function, called whileLoop that takes an array as a parameter, runs the array through a while(...) loop and does a console.log() of each element.

function whileLoop(arr) {
  let array = [...arr]
  while(array.length) {
    console.log(array.shift())
  }
}

// Implement .map(), .filter(), .reduce() as regular javascript functions that take in an array as a parameter, but do the same things as the real functions.

function map(arr, cb) {
  let output = [];
  for(let i=0; i<arr.length;i++){
    output.push(cb(arr[i]))
  }
  return output
}

function filter(arr, cb) {
  let output = [];
  for(let i=0; i<arr.length;i++){
    if(cb(arr[i])) output.push(arr[i])
  }
  return output
}

function reduce(arr, cb, init) {
  for(let i=0; i<arr.length;i++){
    init = cb(init, arr[i], i)
  }
  return init
}

// ---------------------------------------------------- //

console.log('forLoop()');
forLoop(nums);
console.log('------------------\n\n');

console.log('whileLoop()');
whileLoop(nums);
console.log('------------------\n\n');

console.log('map()');
let squares = map(nums, (val=>val * val));
console.log({squares});
console.log('------------------\n\n');

console.log('filter()');
let odds = filter(nums, (val => !!(val % 2)));
console.log({odds});
console.log('------------------\n\n');

console.log('reduce()');
let sum = reduce(nums, (acc,num) => {
  acc += num;
  return acc;
},0);

console.log({sum});
console.log('------------------\n\n');


// ---------------------------------------------------- //

// Objects

// Begin with the starter code below ...
const people = ['Kookla','Fran','Ollie'];

const stuff = {
  tv: 'huge',
  radio: 'old',
  toothbrush: 'frayed',
  cars: ['Toyota','Mazda']
}

// Using spread and destructuring assignment, create a new array called `newPeople', which is a copy of the `people` array, with a person named 'Odie' added to the beginning and one named 'Garfield' added to the end.

let newPeople = ['Odie', ... people, 'Garfield'];

// Using spread and destructuring assignment, create a new object called `newStuff', which is a copy of the `stuff` object, with a new car added to the end of the `cars` array within it

const newStuff = {...stuff, cars: [...stuff.cars, 'Chevy']};

// Create a `state` object with keys of people and stuff that contain the `people` and `stuff` data.
// Do this using object destructuring assignment

let state = {people, stuff};

// Using spread and destructuring assignments, create a new object called `newSate`, repeating the `newPeople` and `newStuff` steps above but directly within the people and stuff nodes of the state object (don't just spread in `newPeople` and `newStuff`)

let newState = {people: ['Odie', ...state.people, 'Garfield'], stuff: {...state.stuff, cars: [...state.stuff.cars, 'Nissan']}};

// Prove that the original people, stuff, and state are unchanged.
// const people = ['Kookla','Fran','Ollie'];

console.log({people});
console.log('------------------\n\n');

console.log({newPeople});
console.log('------------------\n\n');

console.log({stuff});
console.log('------------------\n\n');

console.log({newStuff});
console.log('------------------\n\n');

console.log({state});
console.log('------------------\n\n');

console.log({newState});
console.log('------------------\n\n');