difference between var and let and const in javascript
var variable1 // declared using var
const variable2 // declared using const
myFunction1();
function myFunction1() {
variable1 = "hello!";
console.log(variable1);
// "hello!"
}
myFunction2();
function myFunction2() {
variable2 = "hello!";
// error: variable2 is a constant and can not be redifined
}
myFunction3(true);
myFunction3(codition) {
if(condition) {
let variable3 = "helo!" // declared using const
}
variable3 = "hello!";
// error: variable3 is out of scope
}
/*
Therefore,
var:
-can be declared outside any function to be used inside any function
-can be declared inside any function or any other {} which are of only if or if-else or switch etc. and can be used anywhere inside the function
-can be changed again and again anywhere
let:
-can be declared outside any function to be used inside any function
-if declared inside any function or any other {} which are of only if or if-else or switch etc. and can't be used anywhere inside the function and can be only used inside statement
- can be changed again and again only inside the statement in which they are made in
const:
-can be declared outside any function to be used inside any function
-can be declared inside any function or any other {} which are of only if or if-else or switch etc. and can be used anywhere inside the function
-cannot be changed again and agan anywhere, if tried to, will result in an error
*/