How JavaScript works: inside the V8 engine?

Question

Each Browser has own Engine for JavaScript, so if I want to learn how JavaScript works, I must learn about all the Engines?

Do the Engines translate the Code in the same Way?

• Amadan: Unless you are looking to optimise nanoseconds, which extremely few people need, you do not need to know about JS engines. It is sufficient to know which features are implemented and which are not: caniuse.com and MDN are helpful websites for that. For example, flatMap is not yet widely implemented and it would be better to stay away from it. Rather than studying engines, it is much more valuable to study JavaScript itself; MDN and ES spec are the go-to places.
• Cata John: Not all engines translate the code in the same way. You can read about each engine on google. Is not necesarry to learn how they fully work but it can prove usefull to know a few things about what happens behind the hood.

Answer 1

I guess you don't have to unless you want to create enterprise Applications with thousands of users and every millisecond and roundtrip is important for you to safe real money.

Unless you don't want to let your application perform ideal in every single engine. We are just talking about milliseconds over here.

The overall concept over here is the same in every Engine.

If you want to dig deeper into the understanding of how the engines process your code i recommend to check out You don't know JS. It's a book series in 6 parts which you can read online for free.

After reading that I personally got a much better idea of how my code is processed by the engine. And i'm sure that the part were you need to differ between this engines is all about the performance in the millisecond area!

A brief summary of how the engines differ can be found over here: Guide to JavaScript engines. You could also check out the performance guide over here: JavaScript Engine Comparison.

They have also listet more helpful sources!