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45 lines (34 loc) · 1.04 KB
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// ==== Challenge 1: Write your own closure ====
// Write a simple closure of your own creation. Keep it simple!
const foo = 'bar';
function returnFoo () {
return foo;
}
returnFoo();
// ==== Challenge 2: Create a counter function ====
let num = 0;
const counter = () => {
return () => ++num;
};
// Return a function that when invoked increments and returns a counter variable.
// Example usage: const newCounter = counter();
// newCounter(); // 1
// newCounter(); // 2
const newCounter = counter();
newCounter()
newCounter()
// ==== 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.
object {}
let num = 0;
const increment = () => {
return () => ++num;
};
const decrement = () => {
return () => --num;
};
};
counterFactory(increment())