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61 lines (54 loc) · 1.67 KB
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// ==== Challenge 1: Write your own closure ====
// Write a simple closure of your own creation. Keep it simple!
function multiply(x){
return function (y) {
return x * y;
};
}
let multiply2 = multiply(2);
// console.log(multiply2(4)); // returns 8.
// ==== Challenge 2: Create a counter function ====
const counter = () => {
let y = 0;
// Return a function that when invoked increments and returns a counter variable.
return function() {
return y++;
}
};
let addBy1 = counter();
console.log(addBy1());
console.log(addBy1());
// Example usage: const newCounter = counter();
// newCounter(); // 1
// newCounter(); // 2
// ==== Challenge 3: Create a counter function with an object that can increment and decrement ====
const counterFactory = () => {
let x = 0;
// 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.
return {
increment() {
return ++x;
},
decrement() {
return --x;
}
}
};
let count = 8;
let test = counterFactory() ;
// console.log(test.increment());
// console.log(test.increment());
// console.log(test.increment());
// console.log(test.increment());
// console.log(test.increment());
// console.log(test.increment());
// console.log(test.increment());
// console.log(test.decrement());
// console.log(test.decrement());
// console.log(test.decrement());
// console.log(test.decrement());
let test2 = counterFactory();
// console.log(test2.increment());
// will allow you to create multiple variables storing the information separately.