// closure = A function defined inside of another function,
// the inner function has access to the variables
// and scope of the outer function.
// Allow for private variables and state maintenance
// Used frequently in JS frameworks: React, Vue, Angular
00:00:00 intro
00:00:31 example 1
00:02:19 example 2
00:07:00 example 3
00:10:08 conclusion
// ---------- EXAMPLE 1 ----------
function outer(){
const message = "Hello";
function inner(){
console.log(message);
}
inner();
}
message = "Goodbye";
outer();
// ---------- EXAMPLE 2 ----------
function createCounter() {
let count = 0;
function increment() {
count++;
console.log(`Count increased to ${count}`);
}
function getCount() {
return count;
}
return {increment, getCount};
}
const counter = createCounter();
counter.increment();
counter.increment();
counter.increment();
console.log(`Current count: ${counter.getCount()}`);
// ---------- EXAMPLE 3 ----------
function createGame(){
let score = 0;
function increaseScore(points){
score += points;
console.log(`+${points}pts`);
}
function decreaseScore(points){
score -= points;
console.log(`-${points}pts`);
}
function getScore(){
return score;
}
return {increaseScore, decreaseScore, getScore};
}
const game = createGame();
game.increaseScore(5);
game.increaseScore(6);
game.decreaseScore(3);
console.log(`The final score is ${game.getScore()}pts`);
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