If you’ve been coding in JS for 5 years, chances are you USE closures all the time. Have you ever used a callback function? Closure. Have you ever used a variable in a factory function or constructor to get data privacy? Closure. Have you ever used partial application or curry? Those use closures, too.

Even if you don’t do those things, people on your teams will take advantage of closures and you NEED to understand what’s going on.

Closures are so important and pervasive in JS that nearly all competent JS job interviewers ask “what is a closure?”, and nearly 100% of the time, not knowing the answer will cost you the job, or cost you money because they won’t consider you a senior developer.

I’ve been hiring JS devs and working with JS hiring managers for years and I’ve probably seen that exact scenario unfold a thousand times.

So, you can call me a bully for telling the truth, or you can realize that it’s a topic you can’t afford to glance over and resolve to learn it now.

Now here is the difference between me giving you a dose of harsh reality and a bully. I’m not judging you for it. Maybe before I said something, you didn’t know the importance of it. Maybe you’ve been busy trying to learn other things. The point is, I don’t know why you don’t know it yet, and I don’t care.

What I do care about is that you learn it, because I do know that it will help you a lot. That’s why I wrote the article, and it’s why, right now, I’m offering to tutor you on the topic via video chat.

You can learn closures. I believe in you.

I promise I won’t be mean. Instead, I’ll explain the concept, answer your questions in a non-judgemental way, and pair program with you while you practice until you have it locked down and memorized.

Bullies are trying to tear you down to make their own fragile egos feel better about themselves. I’m trying to build you up and prepare you for the challenges that JS devs face on the job every day.

There is a really big difference.