It is a simple question, why are var1 and var2 undefined .
I was trying to learn closures in javascript and added a parameter but not sure why it is undefined.
var closureFunction = function(var1,var2){
var privateVar = var1+var2;
console.log("Sum of "+ var1 +" and "+ var2+"");
return function(){return privateVar;}
}();
console.log(closureFunction(2,3));
When you use brackets () after a function, it gets executed immediately. And in this case you have not passed any parameter there.
It can go two ways.
var closureFunction = function(var1,var2){
var privateVar = var1+var2;
console.log("Sum of "+ var1 +" and "+ var2+"");
return function(){return privateVar;}
}(2,3); //prints 'Sum of 2 and 3'
console.log(closureFunction()); //prints '5'
Or you can pass parameters in steps
var closureFunction = function(var1){
return function(var2 ){
console.log("Sum of "+ var1 +" and "+ var2+"");
return var1 + var2;
}
}(2); //just return a 'closure' function
console.log(closureFunction(3)); //prints 'Sum of 2 and 3 5'
or you can execute it later.
var closureFunction = function(var1){
return function(var2 ){
console.log("Sum of "+ var1 +" and "+ var2+"");
return var1 + var2;
}
};
var x = closureFunction(2); //return a 'closure' function
console.log(x(3)); //prints 'Sum of 2 and 3 5'
You have to call the closure once its available.
var closureFunction = function(var1, var2) {
var privateVar = var1 + var2;
console.log("Sum of " + var1 + " and " + var2 + "");
return function() {
return privateVar;
}
};
console.log(closureFunction(2, 3)());