Interpreter: A (core) module part of the language runtime / virtual machine which takes specific 'actions' against a set of expressions expressed in the language whose virtual machine the module is.
Compiler: A (core) module part of the language runtime which 'converts' a set of expressions expressed in the language whose compiler the module is, into a set of instructions native to the architecture where the expressions are run against.
Standard Node.js is built against V8, which compiles every Javascript code snippet into native instructions. You may use --print_code flag in the command line to see which scripts are getting compiled, and compiled into what.
Hope this helps.
Answer from Gireesh Punathil on Stack OverflowInterpreter: A (core) module part of the language runtime / virtual machine which takes specific 'actions' against a set of expressions expressed in the language whose virtual machine the module is.
Compiler: A (core) module part of the language runtime which 'converts' a set of expressions expressed in the language whose compiler the module is, into a set of instructions native to the architecture where the expressions are run against.
Standard Node.js is built against V8, which compiles every Javascript code snippet into native instructions. You may use --print_code flag in the command line to see which scripts are getting compiled, and compiled into what.
Hope this helps.
V8 engine compiles javascript to a sequence of machine code instructions, one function at a time (usually, functions are not compiled until the first call).
V8 parses the code and extracts an AST (abstract syntax tree), performs scope analysis in order to understand to which context a symbol refers to, and translates it to machine code instructions.
As you mentioned, V8 is highly focused on performance: besides the full compiler that compiles each function, V8 consists of extra compiler which is responsible for optimizing blocks that identified as frequently used (Known as the Crankshaft)
So no, there's no interpretation of javascript code, but translation and execution of a machine code.
Better question
If NodeJS is interpreted and not compiled, then why do I have to restart the server after every change?
Let's say I'm using Express, why can't I modify a method and simply reload the URL like PHP or Perl? Why do I have to keep restarting the server all the time?
The purpose of node.js is to run JavaScript code outside of a browser right? And it does that by including the same javascript compiler that every modern browser has?