console.
log(""); is use for print
-js is dynamic type its take atomatically data type of data
- case sensitive languge
-variable declarition
var=redeclar same name variable
let= one time you declar variable then you do
not declare same name variable
const = do not redeclare or do not update
prefere write in capital letter
-data type
-number
-string
-boolean:-true or flase
-undefined:-every vrialbe with out intilazation is undefined
-null:-variable with intilize null then type of variable is object
-bigint
-symbol
-object:-colletion of variable
-object declaration
let student={
fullName:"desai",
age:19,
result:pass,
};
-to access any one variable
student["age"]
student.age
-opratore
+ - / * % **(^)->exponone
-asignment opertore
+= :- a+=1 a=a+1
-comparision operator
== equle to
=== equel to & type
!= not equal to
!== not equal and type
-str.length
its shw the number of string how many character in string --
varstring.lenth
-for of loop
for in loop
-template litrel
use ombination to print string and number
let specialstring= `this s litrel ${1+2}'
string method
str.touppercase() :-its not change the orgin string but its give the
return vlue ==immutable string
str.tolowercase()
-str.trim() =clear starting and ending white space not clear space between two word
-string is immutable :-not changed with index
-array is muteable :- is it changed with help of index
-array method
Push() :-add end of array first letter is capital
concat()
unshift() :- add to start
Pop():-delete at end and return first letter is capital
shift() :delete at starting poimt and return
slice() :-return a piece of array in form of orginal but give return
splice() :- change original array(add,remove.replace)
-function statement
function sum(a,b){
return a+b;}
in function we write [return s;]then after this line no any one line
execute in fuction block of code
-arrow function
const functionname=(pra1,pra2)=>{
}
we write only function name then print all definition we write after =
to
but pass with argument then answer print
-for each array used for access arr in every index its also called higher order
function or higher order method
higher order means one function that pass prametter a another function
arr.foreach(function name);
arr.foreach(function he(val){
consol.log(val);});
map its array method work like foe each work in every array but give new array
thats result of array we write
-filter
its is array method that is filter array value with condition if condition is
right then that return a vlue and does not right then isn't return wrok like
filtering
-reduce
perform a operation &reduce the ary to a single value .its return a single
value
-in js we write window.filename then print our file code of html
js store html code in from object document
