How does JavaScript retain variables within closures but discard unused ones? For example:
function genCounter() {
let num = 0;
return function addOne() {
return ++num;
};
}
its cool how js keeps the var cuz the inner fn holds a refernce to it, so even if no one else uses it the blox isnt gc’ed. its all about lexical scopin where closure saves the enviroment
JavaScript closures have often intrigued me as I worked on various projects. In contrast to many languages that might lose inner variable context once a function finishes executing, closures retain a reference to the lexical environment at creation time. This means that even if a variable is not directly used outside its original function, it still remains available for later use through the inner function. In my experience, this feature is particularly useful for creating private variables while also highlighting the importance of understanding memory management in JavaScript.
In my experience, JavaScript’s handling of closures essentially revolves around capturing the scope of a function at the time of its creation. When a function is defined inside another function, the inner function retains access to the outer variables, even after the outer function has finished execution. This happens because JavaScript stores a reference to the variables rather than the actual values. As long as a reference exists, the garbage collector will not clear these variables. It’s an elegant solution to maintain state persistence while also allowing encapsulation of data.