10 useful js features that you should know.

lets start —

1)Primitve data-

in js , primite data is not an object and has no methods . there are 7 priminte data types.

they are -

string,
number,
bigint, 
boolean, 
undefined,
symbol,
null,

2)Checking a Type

by using typeof operator ,you can check the types

just like this -

console.log(typeof “am i joke to you?”)
“string” 
console.log(typeof false) 
console.log(typeof true)
“boolean”
console.log(typeof 1000) 
“number”

3) functions with default parameter-

a default argument is a value that is automatically assigned by the computer if we don’t provide a value for the argument with a default value.

here is the example —

function multiply(a, b = 1) { return a * b; }
here , 

in this above code , b=1 is default parameter. if we don’t provide any value for b it will automatically assigne as b=1 that is called default parameter.

4)Arrow Functions-

arrow function is one of the features of es6 . es6 is a version of js. it allows us to create functions in a cleaner way compared to regular functions.

lets see the code ..

//(standard way) 
var add = function(a,b) 
{ return a+ b; } 
console.log(add(5,5)); 
// 10 
// Arrow style
 var add = (a,b) => a+ b; 
console.log(add(5,5)); 
// 10; 

5)let and const Variables

The let statement declares a block scope local variable, optionally initializing it to a value.

we can change variable values when we use let

just like this -

let asdf= 1232
let asdf=343
console.log(asdf)=>343

but, if we use const , we cann’t change variable values.

just do it-

const asdf= 1232
const  asdf=343
console.log(asdf)=>it will showing err.

so, if we need to change the value anytime , than we use let and if we need to declear a specific values that never change , we will use const .

___________that’s for today. thank you