I don't understand the intuition of closures and they turn me off to languages immediately. They feel like a hack from someone who didn't want to store a copy of a parent-scope variable within a function. The idea that I can touch variables that have gone out of scope (and that have ostensibly been GC'd) makes me feel that it is impossible to reason about variable lifetimes when dealing with closures. Is there some p…
I know you've already got a storm of replies, but I'd like to illustrate part of what I love about closure (especially when combined with anonymous objects like in JavaScript): you can replace classes, private vs public, "this", and other features with a simpler, smaller number of features.
const Counter = () => {
let counts = new Map();
return {
reset: () => {
counts = new Map();
},
count: (key) => {
const count = counts.get(key) + 1;
counts.set(key, count);
return count;
}
}
}
const items = ['apple', 'apple', 'banana', 'canteloupe'];
const counter = Counter()
items.forEach(item => {
console.log(item + ": count is", counter.count(item));
})
counter.reset();
// do some more counting now