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// ==== Challenge 1: Write your own closure ====
// Write a simple closure of your own creation. Keep it simple!
function addNumbers() {
// Local free variable
let x = 1;
function sumNumbers() {
let y = 2;
console.log(`The new sum is: ${x + y}`);
}
// Here shows the global variable can be manipulated outside the environment record
x++;
return sumNumbers;
}
let z = addNumbers();
z();
// ==== Challenge 2: Create a counter function ====
const counter = () => {
// Return a function that when invoked increments and returns a counter variable.
let counter = 0;
function countUp() {
counter++;
console.log(`The new count is: ${counter}`);
}
return countUp;
};
// Example usage: const newCounter = counter();
// newCounter(); // 1
// newCounter(); // 2
let plusCounter = counter();
plusCounter();
plusCounter();
/* STRETCH PROBLEM, Do not attempt until you have completed all previous tasks for today's project files */
// ==== Challenge 3: Create a counter function with an object that can increment and decrement ====
const counterFactory = () => {
// Return an object that has two methods called `increment` and `decrement`.
// `increment` should increment a counter variable in closure scope and return it.
// `decrement` should decrement the counter variable and return it.
let counter = 0;
return {
increment: function() {
let result = counter++;
return result;
},
decrement: function() {
let result = counter--;
return result;
}
};
};
let number = counterFactory();
number.increment();
number.increment();
number.increment();
number.decrement();
console.log(`The new stretch number count is: ${number.increment()}`);