Building a JavaScript runtime in one month
themackabu.dev
themackabu.dev
- how do you exactly know how javascript works inside out?
- i am assuming it is not the most feasible of tasks to sit through the v8 source code with half a million files inside and figure out what part does what
- what level of c/c++ is actually needed to pull something off like this and if you are a beginner who can write some basic data structures and sorting functions,
- what is the roadmap to go from here to the point where you are writing your own browser engine or game engine or drivers for some hardware devices?
- Read the specification in-depth and understand it well.
- Just testing, if you know JavaScript you can test it in other runtimes, create tests around the methods and then you know how it works well. This is usually more for edge cases though, like what happens if you mutate the 3rd argument of Array.map?
- Look at other implementation's internals, as you said.
> how do you exactly know how javascript works inside out?
Javascript has pretty detailed specifications. They're not exhaustive, but the article here does mention that in some of the dark corner cases they compared behavior against other existing Javascript engines.
There's also a very comprehensive test suite (Test262) that comprises almost 40,000 unit tests that exercise various aspects of the language that a new implementation can use to get a pretty good view of how much their new engine conforms to the specification.