console.log(null == undefined);
console.log(null == undefined);
true
console.log(false == '0');
console.log(false === '0');
console.log(false == '0');
console.log(false === '0');
true, false
(true + false) >= 2 - true;
(true + false) >= 2 - true;
true
console.log(personId);
var personId = 11;
console.log(personId);
var personId = 11;
undefined
console.log(personId);
let personId = 11;
console.log(personId);
let personId = 11;
Uncaught ReferenceError: personId is not defined
let personId = 13;
console.log(personId);
let personId = 13;
console.log(personId);
13
let personId
console.log(personId);
let personId
console.log(personId);
undefined
let personId = 15;
{
let personId = 8000;
}
console.log(personId);
let personId = 15;
{
let personId = 8000;
}
console.log(personId);
15
{
let personId = 9000;
}
console.log(personId);
{
let personId = 9000;
}
console.log(personId);
ReferenceError: personId is not defined
function editPersonId() {
personId = 16;
}
let personId = null;
editPersonId();
console.log(personId)
function editPersonId() {
personId = 16;
}
let personId = null;
editPersonId();
console.log(personId)
16
let id = 17;
for (let id = 0;id < 5;id++)
{
}
console.log(id);
let id = 17;
for (let id = 0;id < 5;id++)
{
}
console.log(id);
17
let editFunctions = [];
for (var i = 5; i < 10; i++) {
editFunctions.push(function() {return i;});
}
console.log(editFunctions[0]());
let editFunctions = [];
for (var i = 5; i < 10; i++) {
editFunctions.push(function() {return i;});
}
console.log(editFunctions[0]());
10
let editFunctions = [];
for (let i = 5; i < 10; i++) {
editFunctions.push(function() {return i;});
}
console.log(editFunctions[0]());
let editFunctions = [];
for (let i = 5; i < 10; i++) {
editFunctions.push(function() {return i;});
}
console.log(editFunctions[0]());
5
const PI = 3.14;
const ADDRESS = '10.0.0.1';
console.log(PI);
console.log(ADDRESS);
const PI = 3.14;
const ADDRESS = '10.0.0.1';
console.log(PI);
console.log(ADDRESS);
3.14, 10.0.0.1
const PI;
const ADDRESS;
console.log(PI);
console.log(ADDRESS);
const PI;
const ADDRESS;
console.log(PI);
console.log(ADDRESS);
Uncaught SyntaxError: Missing initializer in const declaration
const ADDRESS = 'localhost';
ADDRESS = '10.0.0.1'
console.log(ADDRESS);
const ADDRESS = 'localhost';
ADDRESS = '10.0.0.1'
console.log(ADDRESS);
Uncaught TypeError: Assignment to constant variable.
const PI= 3.14;
if (PI > 0) {
const PI = -3.14;
}
console.log(PI);
const PI= 3.14;
if (PI > 0) {
const PI = -3.14;
}
console.log(PI);
3.14
const myConstObject = {mutableProperty: 10};
myConstObject.mutableProperty = 20;
console.log(myConstObject.mutableProperty);
const myConstArray = [30];
myConstArray.push(40);
console.log(myConstArray);
const myConstObject = {mutableProperty: 10};
myConstObject.mutableProperty = 20;
console.log(myConstObject.mutableProperty);
const myConstArray = [30];
myConstArray.push(40);
console.log(myConstArray);
20, [30,40]
var getPhone = () => "9"
console.log(typeof getPhone);
var getPhone = () => "9"
console.log(typeof getPhone);
function
var getPhone = () => "9"
console.log(getPhone());
var getPhone = () => "9"
console.log(getPhone());
9
var getPhone =
version => "Note " + version
console.log(getPhone(10));
var getPhone =
version => "Note " + version
console.log(getPhone(10));
Note 10
var getPoints =
(count,lifes) => count + (200 * lifes);
console.log(getPoints(9000,2));
var getPoints =
(count,lifes) => count + (200 * lifes);
console.log(getPoints(9000,2));
9400
var getPoints = (count,lifes) => {
var lifeby = lifes * 200;
return count + lifeby;
}
console.log(getPoints(9000,2))
var getPoints = (count,lifes) => {
var lifeby = lifes * 200;
return count + lifeby;
}
console.log(getPoints(9000,2))
9400
document.addEventListener('click', function() {
console.log(this);
});
document.addEventListener('click', function() {
console.log(this);
});
#document
document.addEventListener('click',
() => console.log(this));
document.addEventListener('click',
() => console.log(this));
Window {parent: Window, opener: null, top: Window, length: 0, frames: Window, …}
var post = {
postId: 604,
read: function () {
console.log(this);
}
};
post.read();
var post = {
postId: 604,
read: function () {
console.log(this);
}
};
post.read();
{postId: 604, read: ƒ}
var post = {
postId: 604,
read: () => console.log(this)
};
post.read();
var post = {
postId: 604,
read: () => console.log(this)
};
post.read();
Window {parent: Window, opener: null, top: Window, length: 0, frames: Window, …}
var post = {
postId: 604,
read: function () {
return () => console.log(this.postId);
}
};
post.read()();
var post = {
postId: 604,
read: function () {
return () => console.log(this.postId);
}
};
post.read()();
604
var post = {
postId: 604,
read: function () {
return () => console.log(this.postId);
}
};
var newPost = {
postId: 198,
};
post.read().call(newPost);
var post = {
postId: 604,
read: function () {
return () => console.log(this.postId);
}
};
var newPost = {
postId: 198,
};
post.read().call(newPost);
604
var post = {
postId: 604,
read: function () {
return () => console.log(this.postId);
}
};
var newPost = {
postId: 198,
};
post.read().bind(newPost)();
var post = {
postId: 604,
read: function () {
return () => console.log(this.postId);
}
};
var newPost = {
postId: 198,
};
post.read().bind(newPost)();
604
var getScore = ()
=> 9000;
console.log(typeof getScore);
var getScore = ()
=> 9000;
console.log(typeof getScore);
Uncaught SyntaxError: Unexpected token '=>'
var getScore = () => 9000;
console.log(getScore.hasOwnProperty("prototype"));
var getScore = () => 9000;
console.log(getScore.hasOwnProperty("prototype"));
false
var getGame = function(id = 0,type="none") {
console.log(id + ", " + type);
}
getGame(undefined, "RPG");
var getGame = function(id = 0,type="none") {
console.log(id + ", " + type);
}
getGame(undefined, "RPG");
0,RPG
var getTotalScore = function(score = 0,lives = 0,
addscore = lives * 200) {
console.log(score + addscore);
};
getTotalScore(5000,2);
var getTotalScore = function(score = 0,lives = 0,
addscore = lives * 200) {
console.log(score + addscore);
};
getTotalScore(5000,2);
5400
var generatePoints = () => 200;
var getTotalScore = function(score = 0,lives = 0,
addscore = lives * generatePoints()) {
console.log(score + addscore);
};
getTotalScore(5000,2);
var generatePoints = () => 200;
var getTotalScore = function(score = 0,lives = 0,
addscore = lives * generatePoints()) {
console.log(score + addscore);
};
getTotalScore(5000,2);
5400
var generatePoints = () => 200;
var getTotalScore = function(score = 0,lives = 0,
addscore = lives * generatePoints()) {
console.log(arguments.length);
};
getTotalScore(5000,2);
var generatePoints = () => 200;
var getTotalScore = function(score = 0,lives = 0,
addscore = lives * generatePoints()) {
console.log(arguments.length);
};
getTotalScore(5000,2);
2
var getName = function(name = defaultname, defaultname = "MR"){
console.log(defaultname + " " + name);
}
getName();
var getName = function(name = defaultname, defaultname = "MR"){
console.log(defaultname + " " + name);
}
getName();
Uncaught ReferenceError: Cannot access 'defaultname' before initialization
var getName = function(name = defaultname, defaultname = "MR"){
console.log(defaultname + " " + name);
}
getName("Cezary");
var getName = function(name = defaultname, defaultname = "MR"){
console.log(defaultname + " " + name);
}
getName("Cezary");
MR Cezary
var getName = new Function("name = 'Cezary'","return name");
console.log(getName());
var getName = new Function("name = 'Cezary'","return name");
console.log(getName());
Cezary
var showTags = function (postId, ...tags){
console.log(tags instanceof Array);
};
showTags(777,"Java","Wzorce-Projektowe","C#");
var showTags = function (postId, ...tags){
console.log(tags instanceof Array);
};
showTags(777,"Java","Wzorce-Projektowe","C#");
true
var showTags = function (postId, ...tags){
console.log(tags);
};
showTags(777,"Java","Wzorce-Projektowe","C#");
var showTags = function (postId, ...tags){
console.log(tags);
};
showTags(777,"Java","Wzorce-Projektowe","C#");
["Java", "Wzorce-Projektowe", "C#"]
var showTags = function (postId, ...tags){
console.log(tags);
};
showTags(777);
var showTags = function (postId, ...tags){
console.log(tags);
};
showTags(777);
[]
var showTags = function (postId, ...tags){};
console.log(showTags.length);
var showTags = function (postId, ...tags){};
console.log(showTags.length);
1
var showTags = function (postId, ...tags){
console.log(arguments.length);
};
showTags(777,"Java","Wzorce-Projektowe","C#");
var showTags = function (postId, ...tags){
console.log(arguments.length);
};
showTags(777,"Java","Wzorce-Projektowe","C#");
4
var showTags = new Function("...tags", "return tags;");
console.log(showTags("Java","Wzorce-Projektowe","C#"));
var showTags = new Function("...tags", "return tags;");
console.log(showTags("Java","Wzorce-Projektowe","C#"));
["Java", "Wzorce-Projektowe", "C#"]
var values = [11,12,33,44,13,45];
var maxValue = Math.max(...values);
console.log(maxValue);
var values = [11,12,33,44,13,45];
var maxValue = Math.max(...values);
console.log(maxValue);
45
var values = [11,12,33,44,13,45];
var valuesArray = [...values];
console.log(valuesArray );
var values = [11,12,33,44,13,45];
var valuesArray = [...values];
console.log(valuesArray );
[11,12,33,44,13,45]
var values = [,,,,];
var valuesArray = [...values];
console.log(valuesArray );
var values = [,,,,];
var valuesArray = [...values];
console.log(valuesArray );
[undefined, undefined, undefined, undefined]
var values = [1,2,3,4,];
var valuesArray = [...values];
console.log(valuesArray );
var values = [1,2,3,4,];
var valuesArray = [...values];
console.log(valuesArray );
[1,2,3,4]
var valuesArray = [...[1,2,3,4,]];
console.log(valuesArray );
var valuesArray = [...[1,2,3,4,]];
console.log(valuesArray );
[1, 2, 3, 4]
var maxNumber = Math.max(..."987654321");
console.log(maxNumber);
var maxNumber = Math.max(..."987654321");
console.log(maxNumber);
9
var wordsArray = ["CEZ",..."WAL",
"PO SCIANIE"];
console.log(wordsArray);
var wordsArray = ["CEZ",..."WAL",
"PO SCIANIE"];
console.log(wordsArray);
["CEZ", "W", "A", "L", "PO SCIANIE"]
var price = 7.99, tax = 0.2;
var product = {
price,
tax,
"calulacte priceWithTax"() {
return this.price * this.tax;
}
};
console.log(product["calulacte priceWithTax"]());
var price = 7.99, tax = 0.2;
var product = {
price,
tax,
"calulacte priceWithTax"() {
return this.price * this.tax;
}
};
console.log(product["calulacte priceWithTax"]());
1.598
var field = 'dynamicPrice';
var field2 = 'dynamicTax'
var price = 7.99, tax = 0.2;
var product = {
[field] : price,
[field2 ] : tax ,
};
console.log(product);
var field = 'dynamicPrice';
var field2 = 'dynamicTax'
var price = 7.99, tax = 0.2;
var product = {
[field] : price,
[field2 ] : tax ,
};
console.log(product);
{dynamicPrice: 7.99, dynamicTax: 0.2}
var field = 'dynamicPrice';
var field2 = 'dynamicTax'
var price = 7.99, tax = 0.2;
var product = {
[field + "-1"] : price,
[field2 + "-1"] : tax ,
};
console.log(product);
var field = 'dynamicPrice';
var field2 = 'dynamicTax'
var price = 7.99, tax = 0.2;
var product = {
[field + "-1"] : price,
[field2 + "-1"] : tax ,
};
console.log(product);
{dynamicPrice-1: 7.99, dynamicTax-1: 0.2}
var codes = "CZEF";
for (var code of codes)
{
console.log(code);
}
var codes = "CZEF";
for (var code of codes)
{
console.log(code);
}
C,Z,E,F
var post = {id:11,title:"m",content:"l"};
for (var p of post)
{
console.log(p);
}
var post = {id:11,title:"m",content:"l"};
for (var p of post)
{
console.log(p);
}
Uncaught TypeError: post is not iterable
var obj = {
name: "Simon",
age: "20",
}
for(var propt in obj){
console.log(propt + ': ' + obj[propt]);
}
var obj = {
name: "Simon",
age: "20",
}
for(var propt in obj){
console.log(propt + ': ' + obj[propt]);
}
name: Simon, age :20
let numer = 888;
console.log('Numer : ${numer}');
let numer2 = '888';
console.log('Numer : ${numer2}');
let numer3 = 999;
console.log(`Numer : ${numer3}`);
let numer = 888;
console.log('Numer : ${numer}');
let numer2 = '888';
console.log('Numer : ${numer2}');
let numer3 = 999;
console.log(`Numer : ${numer3}`);
Numer : ${numer},Numer : ${numer2}, Numer : 999
let what = `K
O
C
H
A JAVASCRIPT`;
console.log(what);
let what = `K
O
C
H
A JAVASCRIPT`;
console.log(what);
K
O
C
H
A JAVASCRIPT
function showCommand(command) {
let ile = 3;
console.log(command);
}
let ile = 20;
showCommand(`Kup ${ile} jabłek`);
function showCommand(command) {
let ile = 3;
console.log(command);
}
let ile = 20;
showCommand(`Kup ${ile} jabłek`);
20
function process(segments,...textes) {
console.log(segments);
console.log(textes);
}
let headerText = "Blog Stefana";
let title = "Co nowego ES2030";
process `-> ${headerText} wpisy ${title} <-`;
function process(segments,...textes) {
console.log(segments);
console.log(textes);
}
let headerText = "Blog Stefana";
let title = "Co nowego ES2030";
process `-> ${headerText} wpisy ${title} <-`;
["-> ", " wpisy ", " <-"]
["Blog Stefana",
"Co nowego ES2030"]
let programmersSalary =
[3000,5000,7200,8500,10000,15000];
let [lowest,low,avarage,ok,yes,hight] =
programmersSalary;
console.log(lowest);
console.log(avarage);
let programmersSalary =
[3000,5000,7200,8500,10000,15000];
let [lowest,low,avarage,ok,yes,hight] =
programmersSalary;
console.log(lowest);
console.log(avarage);
3000, 7200
let programmersSalary =
[3000,5000,7200,8500,10000,15000];
let [lowest,,,,,hight] = programmersSalary;
console.log(hight);
let programmersSalary =
[3000,5000,7200,8500,10000,15000];
let [lowest,,,,,hight] = programmersSalary;
console.log(hight);
15000
let programmersSalary =
[3000,5000,7200,[8500,10000,15000]];
let [lowest,low,avarage,
[seniorlowest,senioravarage, seniorHigh]] =
programmersSalary;
console.log(seniorlowest);
let programmersSalary =
[3000,5000,7200,[8500,10000,15000]];
let [lowest,low,avarage,
[seniorlowest,senioravarage, seniorHigh]] =
programmersSalary;
console.log(seniorlowest);
8500
let game = {
title: 'Mortal Kombat 2',
desc: 'bla bla',
platform: 'Amiga'
};
let {title,desc} = game;
console.log(title);
let game = {
title: 'Mortal Kombat 2',
desc: 'bla bla',
platform: 'Amiga'
};
let {title,desc} = game;
console.log(title);
Mortal Kombat 2
let [title,desc] = undefined;
console.log(`title ${title} desc ${desc}`);
let [title,desc] = undefined;
console.log(`title ${title} desc ${desc}`);
Uncaught TypeError: undefined is not iterable
let [title,desc] = null;
console.log(`title ${title} desc ${desc}`);
let [title,desc] = null;
console.log(`title ${title} desc ${desc}`);
Uncaught TypeError: null is not iterable
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>Szybki trening</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<script type="module" src="/module-first.js" ></script>
<script type="module" src="/main.js" ></script>
</head>
<body>
</body>
// Plik main.js
import value from '/module-first.js';
console.log(value);
// Plik module-first.js
export let worstGameEver = "Last of US 2";
let game = "Settlers";
export default game;
???
class Solider {
constructor() {
console.log('buduje Solider');
}
}
class SoftwareSolider extends Solider {
constructor() {
//super();
console.log('buduje SoftwareSolider');
}
}
let s = new SoftwareSolider();
???