javascript

For buisness applications and wep app.

unify for all

• nodejs - sudo apt install nodejs, sudo apt install npm
• typescript

Fixing error

• in console
• freely use white space
• commenting

1. // ___ single comment
2. /* */

variable and constants

declaring variables

• let

• int, float, boolean, string
• camalcase - accountNumber
• private - _accountNumber
• automatically generated - $accountNumber
• __proto__ - non standard features

• const

• fixed

• var

• variable naming variables common error variables

Types and operators

pgm flow

• if ... else - conditional
• comparinf === ==
• Truthy Falsy
• The ternary Operator
• Blockscope
• for, while...

Ternarty operators

(condition)? true statement: false statement;

Functions

function showMessage(){

}

showMessage();

let showMessage = function(message, firstName){
    console.log(message, firstName);
}

showMessage(message, firstName);

Objects and the DOM

properties

let person = {
    name : "Revathy",
    hour : 40,
    Time : True
};

object methods

let person = {
    name : "Revathy",
    hour : 40,
    Time : True,
    showInfo: function(){
        showmessage(this.name) // property name
    }
};

person.showInfo();
showMessage( typeof person.showInfo) // function

The objects are at https://developer.mozilla.org/en-US/docs/Web/JavaScript.

DOM (Document Object Model)

HTML element - style

ARRAYS

• []
• Array.of()

manupulating array. values.push('value') - pushing value to last element of array values. values.pop() -take last element. values.shift() - first element take out. values.unshift('value') -add the element to first.

slice() and splice()

values = ['1','2'];
newValue = values.slice(1)// 1 only

splice