Modern JavaScript engines (like V8 in Chrome or SpiderMonkey in Firefox) use JIT compilation, essentially a mix of both compilation and interpretation.
- The code is initially translated into an intermediate format (like bytecode).
- During runtime, frequently executed parts of the code are compiled into machine code for faster performance. This approach offers a balance between the flexibility of interpretation and the speed of compiled languages.
So basically just compiled?
No. Because the whole code isn’t compiled. Only frequent parts are compiled. Other parts might be interpreted.
Purpose? Good balance between speed and development flexibility.