JavaScript

JavaScript Types

<!DOCTYPE html>

<head>

<title>Document</title>

</head>

<h1>Hello world!</h1>

<body>

</script>

</body>

</html>

console.log(getMax(1, 5))

function getMax(a, b) {

return (a > b) ? a : b;

}

=====================================================

let person = {

name: 'Mosh',

age: 30

};

for (let key in person)

console.log(key, person[key])

let colors = ['red', 'green', 'blue']

for (let index in colors)

console.log(index, colors[index])

console.log(5 + 5 + '5') //answer 105 ,type string

-------------------------------------------------

const output = fizzBuzz(7)

console.log(output)

function fizzBuzz(input) {

if (typeof input !== 'number')

return 'Not a number';

let strout = '';

if (input % 3 === 0) strout = 'Fizz';

if (input % 5 === 0) strout = 'Buzz';

if ((input % 3 === 0) && (input % 5 === 0)) return 'FizzBuzz';

// console.log(strout);

if (strout !== '') return strout;

else

return input;

Math.ceil

}

-------------------------------------------------

checkSpeed(180)

function checkSpeed(speed) {

speedlimit = 70;

const kmPerPoint = 5;

if (speed < speedlimit + kmPerPoint) {

console.log('Ok');

return;

}

const points = Math.floor((speed - speedlimit) / kmPerPoint);

if (points >= 12)

console.log('Licence suspended');

else

console.log('Points', points);

}

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showNumbers(10)

function showNumbers(limit) {

for (let i = 0; i <= limit; i++) {

if (i % 2 !== 0) console.log(i + ' ' + '"ODD"');

else console.log(i + ' ' + '"EVEN"');

}

=====================================================

const array = [0, null, undefined, '', 2, 4, 7, 4];

countTruthy(array);

function countTruthy(array) {

let count = 0;

for (let item of array) {

if (item) count++;

}

console.log(count);

}

=======================================================

const movie = {

title: 'a',

releaseYear: 2018,

rating: 4.5,

director: 'b'

};

showProperties(movie);

function showProperties(obj) {

for (let key in obj) {

if (typeof obj[key] === 'string') {

console.log(key, obj[key]);

}

=======================================================

console.log(sum(10));

function sum(limit) {

let s = 0;

for (let i = 0; i <= limit; i++) {

if (i % 3 === 0) s += i;

if (i % 5 === 0) s += i;

}

return s;

}

==========================================================

const marks = [90, 100, 50];

console.log(calculateGrade(marks))

function calculateGrade(marks) {

let sum = 0;

let avg = 0;

for (let mark of marks) {

sum += mark;

}

avg = sum / marks.length;

console.log('avg=' + avg)

if (avg < 60) return 'F';

if (avg < 70) return 'D';

if (avg < 80) return 'C';

if (avg < 90) return 'B';

}

==============================================================

showStars(10);

function showStars(rows) {

for (let i = 1; i <= rows; i++) {

let pattern = '';

for (let j = 0; j < i; j++)

pattern += '*'

console.log(pattern)

}

=================================================================

showPrimes(50)

function showPrimes(limit) {

for (let i = 1; i <= limit; i++) {

let count = 0;

for (let j = 1; j <= i; j++) {

if (i % j === 0) count++;

}

if (count === 2) console.log(i);

}

===================================================================

const address = {

street: "pknm",

city: "PTA",

zipCode: "689645"

};

function showAddress(address) {

for (let key in address)

console.log(key, address[key])

}

showAddress(address);

=====================================================================

let address = new Address('a', 'b', 'c');

for (let key in address)

console.log(key, address[key])

//console.log(address);

console.log(address.showName('Jobin'))

//Constructor Function

function Address(street, city, zipCode) {

this.street = street;

this.city = city;

this.zipCode = zipCode;

this.showName = function(name) {

return name + " Jose";

}

=============================================

Constructor Function

function Address(street, city, zipCode) {

this.street = street;

this.city = city;

this.zipCode = zipCode;

this.showName = function(name) {

return name + " Jose";

}

let address1 = new Address('a', 'b', 'c');

let address2 = new Address('a', 'b', 'c');

let address3 = address1;

console.log(areEqual(address1, address2));

console.log(areSame(address1, address2));

console.log(areSame(address1, address3));

function areEqual(address1, address2) {

if (address1.street === address2.street &&

address1.city === address2.city &&

address1.zipCode === address2.zipCode

)

return true;

else return false;

}

function areSame(address1, address2) {

return address1 === address2;

}

function areSame(address1, address3) {

return address1 === address3;

}

====================================================

let post = {}

post = {

title: 'a',

body: 'b',

author: 'c',

comments: [

{ author: 'a', body: 'b' },

{ author: 'c', body: 'd' },

],

isLive: true

};

function Post(title,body,author){

this.title=title;

this.body=body;

this.author=author;

this.views=0;

this.comments=[];

this.islive=false;

}

console.log(post);

============================================================

section 6 arrays

===================================

const numbers = [3, 4];

numbers.push(5, 6);

numbers.unshift(1, 2);

numbers.splice(2, 0, 'a', 'b')

let outp = numbers.indexOf('a');

console.log(out);

===================================

const numbers2 = [1, 2, 3, 1, 4];

console.log(numbers2.indexOf('1'));

console.log(numbers2.lastIndexOf(1));

console.log(numbers2.includes(1));

console.log(numbers2.indexOf(1, 2));

====================================

var array1 = [5, 12, 8, 130, 44]

var found = array1.find(function(element) {

return element > 10;

});

console.log(found);

const courses = [

{ id: 1, name: 'a' },

{ id: 2, name: 'b' },

];

const course = courses.find(course => course.name === 'a');

console.log(course);

========================================

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

const last = numbers.pop();

console.log(numbers);

console.log(last);

===========================================

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

console.log(numbers);

const last = numbers.pop();

console.log('pop()');

console.log(numbers);

console.log('shift()');

const first = numbers.shift();

console.log(numbers);

console.log('first num =' + first);

console.log('last num =' + last);

===============================================

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

console.log(numbers);

console.log('splice(2,2)');

const splice = numbers.splice(2, 2);

console.log(numbers);

==============================================

const first = [1, 2, 3];

const second = [4, 5, 6];

const combined = first.concat(second)

const combined = [...first, ...second];

const combined = [...first, 'a', ...second, 'b']

console.log(combined);

==============================================

const numbers = [1, 2, 3];

numbers.forEach(function(number) {

console.log(number);

});

numbers.forEach(number => console.log(number));

=================================================

Sort function

//============================

const courses=[

{id:1,name:Node.js}

]

================================

exercise 84

================================

const nums = arrayFromRange(10, 19)

console.log(nums);

function arrayFromRange(min, max) {

let intarray = [];

for (let i = min; i <= max; i++) {

intarray.push(i);

}

return intarray;

}

=======================================

exercise 85

=======================================

const numbers = [1, 2, 3, 4, 'a', '7'];

console.log(includes(numbers, 2))

function includes(array, searchElement) {

for (let item of array) {

if (item === searchElement)

return true;

}

return false;

}

========================================

exec 86

=================

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

const output = except(numbers, [1, 2]);

console.log(output);

function except(array, excluded) {

let retarray = [];

for (let number of array) {

let include = true;

for (let exnum of excluded) {

if (number === exnum) include = false;

}

if (include) retarray.push(number);

}

return retarray;

}

==============================================

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

const output = move(numbers, 1, 2);

console.log('output=' + output);

function move(array, index, offset) {

const position = index + offset;

if (position >= array.length || position < 0) {

console.error('invalid offset');

return;

}

const output = [...array];

const element = output.splice(index, 1)[0];

console.log("element=" + element);

output.splice(position, 0, element)

return output;

}

==============================================

factory fn

======================

function createCircle(radius) {

return {

radius,

draw: function() {

console.log('draw');

}

};

}

========================

OOP es6

========================

class Circle {

constructor(radius) {

this.radius = radius;

this.move = function() {

console.log('Move')

}

const c = new Circle(1);

c.move();

console.log(c.radius);

======================================

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

const count = countOccurrences(numbers, 4);

console.log(count);

function countOccurrences(array, searchElement) {

let count = 0

for (let num of numbers) {

if (num === searchElement) {

count++;

}

return count;

}

===========================================

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

console.log(getMax(numbers))

function getMax(array) {

if (numbers.length === 0) return undefined;

array.reduce((accumulator, current) => {

if (current > accumulator) return current;

return accumulator;

});

}

==============================================

console.log(sum([1, 2, 3, 4, 5]));

function sum(...items) {

if (items.length === 1 && Array.isArray(items[0]))

items = [...items[0]];

return items.reduce((a, b) => a + b);

}

==============================================

const circle = {

radius: 1,

get area() {

return Math.PI * this.radius * this.radius;

}

};

console.log(circle.area);