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closure.js
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66 lines (59 loc) · 2.35 KB
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// ==== Challenge 1: Write your own closure ====
// Write a simple closure of your own creation. Keep it simple!
function parent(){
const parent = 'parent';
console.log(`I am the ${parent} and my closure is. I can't say who my child or grandchild is. I do not have a closure in chrome dev tools, but I am restricted the global window object on the DOM.`);
child();
function child(){
let child = 'child';
console.log(`I am the ${child}. My parent is ${parent}. I can't say who my child is. Since I am accessing the parent variable, my closure is the parent function`);
grandChild();
function grandChild(){
const grandchild = 'grandchild';
console.log(`I am the ${grandchild}. My parent is ${child}, and my grandparent is ${parent}. I have no children. I have two closures. My first closure is child since I use the child variable and because it's located inside the child function. My second closure is parent since I access the parent variable inside of the parent function.`);
}
}
}
parent();
// ==== Challenge 2: Create a counter function ====
// const counter = () => {
// let countVal = 0;
// // Return a function that when invoked increments and returns a counter variable.
// };
const newCounter = function counter(){
let count = 0;
function countUp(){
return count++;
}
countUp();
countUp();
countUp();
console.log(count);
}
newCounter();
// Example usage: const newCounter = counter();
// newCounter(); // 1
// newCounter(); // 2
/* 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.
const counterObj = {
count: 0,
increment: function countUp(){
return counterObj.count++;
},
decrement: function countDown(){
return counterObj.count--;
}
}
console.log(counterObj);
console.log(counterObj.increment());
console.log(counterObj.increment());
console.log(counterObj.increment());
console.log(counterObj.decrement());
console.log(counterObj);
};
counterFactory();