Mark

365 days. 1 book series. Daily JS lessons. I’m committing to reading “You Don’t Know JS Yet” by Kyle Simpson , all 6 books , every day for a year and tweeting everything I learn. If you’re on the same journey, follow along, let’s do this together. 🤝. #365DaysOfYDKJS #YDKJS.

A class in JavaScript is just a blueprint. It becomes real only when you instantiate it with new. The blueprint is nothing. The instance is everything. 🏗️ #JavaScript #YDKJS #365DaysOfYDKJS

Quick JS quiz , What does this return and why? "71" < "70" Drop your answer below 👇 #JavaScript #YDKJS #365DaysOfYDKJS

Most JS devs avoid == because of coercion. But < and > are also coercive , and nobody talks about that. You can't escape coercion in JS. You can only understand it. 💡 #JavaScript #YDKJS #365DaysOfYDKJS

That's Day 6 done. 🎯 Two threads. Coercive comparison and Classes. See you tomorrow for Day 7 ,Modules are up next. 👇 #365DaysOfYDKJS #YDKJS #JavaScript #LearnInPublic

3. A class on its own is not concrete , it's just a blueprint. It only becomes useful when instantiated using the new keyword: jslet greetingInstance = new Greeting("hello") Only after instantiation can you access its behaviour. 🧠 #YDKJS #365DaysOfYDKJS #JavaScript

Day 6 of 365 — #365DaysOfYDKJS 🧵 (2/2) Every program has data and behaviour. Today I learned how JavaScript organises them using Classes. Let's get into it 👇 #YDKJS #JavaScript #LearnInPublic

5. The recommendation isn't to avoid ==. It's to understand it deeply , know when coercion works for you and when it doesn't. Fear of a tool is never the answer. Knowledge is. 💡 Thread 2 coming up next ,Classes & Organisation 👇 #365DaysOfYDKJS #YDKJS #JavaScript #LearnInPublic

4. But when both values are strings, JS does lexicographic (alphabetical) comparison instead: js"71" < "70" // false → "1" ranks higher than "0" alphabetically Not numeric. Not what you'd expect. Know the difference. ✅ #YDKJS #365DaysOfYDKJS #JavaScript

Day 6 of 365 , #365DaysOfYDKJS 🧵 (1/2) Today I learned about Coercive Comparison in JavaScript , and why avoiding == might not be the answer. Let's get into it 👇 #YDKJS #JavaScript #LearnInPublic

If you've been following this series — Which day's content hit the hardest so far? 👇 #365DaysOfYDKJS #YDKJS #JavaScript #LearnInPublic

[1,2,3] === [1,2,3] // false This confuses so many JS developers. === doesn't compare contents ,it compares memory identity. Two separate arrays will never be strictly equal. Ever. 🧠

Quick JS quiz — What does this return? NaN === NaN Drop your answer below 👇

In JavaScript, functions are values. You can pass them around, store them in variables, assign them properties. Most languages don't allow this. JS does. That's powerful. 💡 #JavaScript #YDKJS #365DaysOfYDKJS

@PythonPr This highlights integer division, the Correct answer is 3 ,

Looks simple, right? That’s what every coder said before getting it wrong 🫣 What’s your answer?

@darasoba I didn’t expect to see a post like this today 😂.

Talking to ChatGPT feels like talking Penny, talking to Claude feels like talking to Sheldon. I prefer talking to Penny.