Basic JavaScript ES6

arrays.js

// Array

array = new Array()
array[0] = "Zack";
array[1] = "Unicorn";
array.push('Parrot');
array[8] = "Unidolphin";
array.push('Parrot');
console.log("Array with undefined elements: " + array)

console.log("Non-existing array element: " + array[40])

array.pop()
array.pop()
array.push(['Ladybug','Ladybird'])
array.sort()
array.reverse()
console.log(array)

array2 = ["Love", "Peace"]
console.log("Concatted array: " + array2.concat(['Undestanding']))

console.log("Sliced array: " + array.slice(5,7))

console.log("Joined array: " + array2.join(" * "))

const.js

const myArray = [23,23,23]

myArray.push(3)

console.log(myArray)

myArray.pop()

console.log(myArray)

const myObject = { name: "Chris" }

console.log(myObject.name)

myObject.name = "Dolphin"

console.log(myObject.name)

[23, 23, 23, 3]
[23, 23, 23]
"Chris"
"Dolphin"

functions.js

// Hoisting and functions

hoistedFunction();

const myName = "Chris";

hoistedFunction();

function hoistedFunction() {
  if (!myName){
    console.log(myName);
    console.log("Hoisted Hi !!!" + myName);
  }
  console.log("Hoisted Hi " + myName);
}

var sayHi = function() {
  if (!myName){
    const myName = "BoB";
    console.log("sayHi " + myName);
    console.log("Hi !!!" + myName);
  }
  console.log("Hi " + myName);
}

sayHi();

sayHi();

/*
undefined
"Hoisted Hi !!!undefined"
"Hoisted Hi undefined"
"Hoisted Hi Chris"
"Hi Chris"
"Hi Chris"
*/


// Function expression

const squaredNumber = function(num) {
  return num * num;
}

const numberAdder = function(squarer, num2) {
  //squarer is a function expression!
  return squarer(4) + num2;
}

console.log(numberAdder(squaredNumber,10))


const info = { name: "Chris", age: 31};

//This func will change the original :(
function changeAge(myObj){
  myObj.age = 100;
}

console.log(info); //[object Object] {age: 31, name: "Chris"}
changeAge(info);
console.log(info); //[object Object] {age: 100, name: "Chris"}

const numbers = [1,2,3,4,5]

//This func will change the original :(
function addToArray(arr){
  arr.push(6);
}

console.log(numbers); //[1, 2, 3, 4, 5]
addToArray(numbers);
console.log(numbers); //[1, 2, 3, 4, 5, 6]


// Nested functions == CLOSURES

function squareAndMultiply(num) {
  
  const hey = "hey";
  
  function squarer(x){
 
    console.log(hey); //Closure can access variables from outer func but NOT VICE VERSA
    return x * x;
  }

  return squarer(num) + num;
}

var x = squareAndMultiply(80);

console.log(x);

function formatter(name, surname, age) {
  
  function formatNames(arg1, arg2) {
    return arg1 + " " + arg2;
  }
  
  function dataFormatter(fullName, number) {
    const formattedData = {
      name: fullName,
      age: number
    }
    
    return formattedData;
  }
  
  const n = formatNames(name, surname);
 
  return dataFormatter(n, age);
}

console.log(formatter("Chris","Dolphin",88));

/*
"hey"
6480
[object Object] {
  age: 88,
  name: "Chris Dolphin"
}
*/

functions_advanced.js

// ADVANCED FUNCTIONS

// THIS IS FUNCTION EXPRESSION
var sayHi = function() {
  console.log("Hi!")
}

sayHi();

// ARROW FUNCTIONS - more concise way
var sayHi2 = () => {
  console.log("Hi from arrow function!");
}

sayHi2();

const multiplier = (num1, num2) => { 
  return num1 * num2;
}

console.log(multiplier(3,5));

const users = [
  { name: "Chris", age : 60},
  { name: "Dolpih", age : 5},
  { name:"Parrot", age : 101}
];

//Built-in map func
users.map(function(user) {
  console.log("map " + user.name)
});

const userNameList = users.map(function(user){
  return user.name;
});

console.log(userNameList);

users.map((user) => {
  console.log("arrow => " + user.name)
});

const userAgeList = users.map((user) => {
  return user.age;
});

console.log(userAgeList);

//NORMAL VERSION
function mapUserNames(myArr){
  const lista = myArr.map(function(user) {
  return user.name + " =)";
});
  
  return lista;
}

console.log(mapUserNames(users));

//ARROW VERSION
const mapUserNames2 = (myArr) => myArr.map((user) => user.name + " <3");
  

console.log(mapUserNames2(users));

//ONE LINERS DO NOT REQUIRE { }
const multiply = (x, y) => x * y;

console.log(multiply(5,5));

// DROP () if there's ONE PARAMETER
const square = num => num * num;

console.log(square(3));

// FILTER

const numbers2 = [1,2,3,4,5,6,7,8,9,10];

const filteredNumbers = numbers2.filter(function(num){
  return num % 2 === 1;
});

console.log(filteredNumbers);

const filteredNumbersArray = numbers2.filter(num => num % 2 === 0);

console.log(filteredNumbersArray);

// FOR EACH - built-in function

const doubledNumbers = (num) => {
  const numberContainer = [];
  num.forEach((x) => numberContainer.push(x * 2));
  return numberContainer;
};


// DEFAULT VALUES
const defaultNumber = 8;

const multiplier = (x=defaultNumber,y=1) => x*y;

console.log(multiplier());
console.log(multiplier(5));
console.log(multiplier(5,5));



// arguments is a reserved keyword in JS

function logAllArgs(x,y,z) {
  console.log(arguments);
  //get array of additional, unexpected arguments
  const args = Array.prototype.slice.call(arguments, logAllArgs.length);
  console.log("There are : " + args.sort());
};

logAllArgs(1,"x",false,9,8,7,5,6);

// REST PARAMETERS

function logAllArgs2(x, ...nums) {
  console.log(nums); //nums is an array
  console.log("There are " + nums.length + " ...rest arguments");
  
};

logAllArgs2(1,"x",false,9,8,7,5,6);

function multiplier(multi, ...nums) {
  
  return nums.map( (x) => multi * x )
}
  
console.log(multiplier(100, 1,2,3));



// CONSTRUCTORS
// CREATE new version of a FUNCTION WITH NEW

function Dog(years, breed) {
  this.age = years;
  this.type = breed;
  
  let that = this;
  //Arrow function will inherit context from enclosing context. It will know this of the object
  setInterval(() => {
    console.log(that);
    this.age += 1;
    console.log(this)
  }, 2000);
  
  setInterval(function() {
    console.log(that);
    this.age += 1;
    console.log(this); //This function will not inherit's constructor's context, it needs "that" variable
  }, 2000);
}

const spike = new Dog(3, "Golden German Shephard");
const piesa = new Dog(2, "White Chihuahua");

function test() {
    'use strict';
  console.log(this); //in strick mode this is undefined, otherwise it's 
}
test();

let.js

function sayHi() {
  
  let shouldSayHi = true;
  var reallySayHi = true;
  
  if (shouldSayHi) {
    
    let myName = 'Chris'; //let is scoped to the block
    console.log("Hi " + myName + " " +shouldSayHi );
  }

  console.log("Hi " + myName + " " ); //Can't access let variables!
}

sayHi();

"Hi Chris true"
"error"
"ReferenceError: myName is not defined
    at sayHi (muzemid.js:14:48)
    at muzemid.js:17:1
    at https://static.jsbin.com/js/prod/runner-4.1.7.min.js:1:13924
    at https://static.jsbin.com/js/prod/runner-4.1.7.min.js:1:10866"

objects.js

// Objects are key-value pair collections
// Object literal syntax
var myObject = { 
  1: "Chris",
  2: "Dolphin",
  3: "Parrot",
  phone: {
   mobile: "666-666-666",
  home: "123-33-333"
  }
} 
console.log(myObject.phone['home'])
console.log(myObject['phone']['home'])

// Object syntax
newObject = new Object(); 
newObject['1'] = "Chris"
newObject['xRay'] = 'zray'
newObject['age'] = 17
console.log(newObject)

// Function
function sayHi() {
  console.log("Hi")
}

var donut = {
  type: "coconut",
  glazed: true,
  eat: function() {
    console.log("Yummy!")
  },
  sayType: function() {
    console.log("Type: "+ this.type)
  }
}

donut.eat()
donut.sayType()

ObjectsOutput.txt

3-33-333"
"123-33-333"
[object Object] {
  1: "Chris",
  age: 17,
  xRay: "zray"
}
"Yummy!"
"Type: coconut"

OutputArrays

"Array with undefined elements: Zack,Unicorn,Parrot,,,,,,Unidolphin,Parrot"
"Non-existing array element: undefined"
[undefined, undefined, undefined, undefined, undefined, "Zack", "Unicorn", "Parrot", ["Ladybug", "Ladybird"]]
"Concatted array: Love,Peace,Undestanding"
"Sliced array: Zack,Unicorn"
"Joined array: Love * Peace"

OutputTypes.txt

true
3.141592653589793
"Convert from string to number via + notation: 2"
10
"s"
"Hello world!"
"I WANNA BE BIG"
"i wanna be small"
"true === true    true"
"true == true   true"
"null === false   false"
"null == false   false"
"Boolean(-1) = true"
"Boolean(0) = false"
"Unassigned variable: undefined type: undefined"
"Array is truthy true"
"Empty array is truthytrue"
"Undefined array is falsey false"
"null === undefined false"
"null == undefined true"

switch.js

function fruitLogger(fruit) {
  
  switch (fruit) {
    //uses === for comparison
    case "apple": console.log("It's an apple!"); return;
    case "orange" : console.log("It's an orange!"); break;
    case "candy":
    case "fastfood":
      console.log("Not good!"); break;
    default: console.log("I dunno what it is " + myFruit); break;
  }
}

const myFruit = "orange"

fruitLogger(myFruit)

types.js

//Types in JavaScript

// Numbers

console.log(isNaN(parseInt("jikj + 4")))
console.log(Math.PI)
console.log("Convert from string to number via + notation: " +( +"2"))

//String
console.log("superduper".length)
console.log("Piesa".charAt(3))
console.log("Hello" + " world" + "!")
console.log("i wanna be big".toUpperCase())
console.log("I WANNA BE SMALl".toLowerCase())

//Booleans
var t = true
console.log("true === true    " + (t === true))
console.log("true == true   " + (t == true))

t = null
console.log("null === false   " + (t === false))
console.log("null == false   " + (t == false))

console.log("Boolean(-1) = " + Boolean(-1))
console.log("Boolean(0) = " + Boolean(0))

var unassigned;
console.log("Unassigned variable: " + unassigned + " type: " + typeof(unassigned))

var array = [0, 0, 0]
console.log("Array is truthy " + Boolean(array))

var emptyArray = []
console.log("Empty array is truthy" + Boolean(emptyArray))

var uArray
console.log("Undefined array is falsey " + Boolean(uArray))

console.log("null === undefined " + (null === undefined))
console.log("null == undefined " + (null == undefined))

var.js

function sayHi() {
  
  var shouldSayHi = true;
  var reallySayHi = true;
  
  if (shouldSayHi) {
    
    var myName = 'Chris'; //This variable is scoped to the entire function
    
    if (reallySayHi) {
        var myLastName = "Smith"
    }
  }
  
  /*
  // Hoisting and functions

hoistedFunction();

const myName = "Chris";

hoistedFunction();

function hoistedFunction() {
  if (!myName){
    console.log(myName);
    console.log("Hoisted Hi !!!" + myName);
  }
  console.log("Hoisted Hi " + myName);
}

var sayHi = function() {
  if (!myName){
    const myName = "BoB";
    console.log("sayHi " + myName);
    console.log("Hi !!!" + myName);
  }
  console.log("Hi " + myName);
}

sayHi();

sayHi();
  */
  
  myName = 'Sally';
  myLastName = 'Dolphin'
  console.log("Hi " + myName + " " + myLastName); //I have access to myName variable , but I SHOUDLN'T!
}

sayHi()
console.log(myName) //Can't access it because it's in function's scope

/*"Hi Sally Dolphin"
"error"
"ReferenceError: myName is not defined
    at muzemid.js:23:38
    at https://static.jsbin.com/js/prod/runner-4.1.7.min.js:1:13924
    at https://static.jsbin.com/js/prod/runner-4.1.7.min.js:1:10866"*/