Notes.txt

                                Closure in Java Script


Closure is a feature in java Script where Inner function can Access has an Outer function variable.


Closure has three Scope chains
	
		1.It can access its own variable( the variable within the curly brackets).	
        Example:
                    function outer(){ 	//creating parent function called outer
                    let count=0;
                    function inner(){ 	//creating a child function called inner 
                        count++;    		//counting 
                        console.log(count);
                    }
                    return inner;		 // returning function itself
                    }
                    let result=outer(); 	//return value and assignment and function call
                    result();		 //function call at first time
                    result(); 		// function call at second time

                    let y =outer(); 		//assigning again to outer function 
                    y();			 // function with another variable

		2. It can access parent variables which are outer function variables.
        Example:
                    function outer(){	//creating parent function called outer
                    let a=10;.
                    function inner(){	//creating a child function called inner 
                        let b=20;
                        return a+b;		// access a from outside of the function(outer)
                    }
                    return inner; 		// returning function itself
                    }
                    let result=outer(); 	//return value and assignment and function call
                    console.log(result());	 // print 30 has output

        3. It also can access Global variables.
        Example:
                    let globalVar = 100;		 // global variable

                    function outer() {
                        function inner() {
                            console.log(globalVar); 	// accesses global variable
                        }

                        return inner; 		// inner survives outside → closure
                    }
                    let fn3 = outer();
                    fn3();