Lesson 3 / 28

Running Scripts & the REPL

Two ways to execute JavaScript with Node.

Running a file

Save as hello.js, then run node hello.js in your terminal.

console.log("Hello from Node!");

Output:

Hello from Node!

The REPL

Running node with no file drops you into the REPL — a Read-Eval-Print Loop for quick experiments.

$ node
> 2 + 2
4
> const x = 10
undefined
> x * 2
20
> .exit

Quick check: What does REPL stand for?

  • Read-Eval-Print Loop
  • Run-Execute-Process Line
  • Remote Execution Protocol Layer
Answer

Read-Eval-Print Loop — It reads your input, evaluates it, prints the result, and loops.