REPL stands for Read-Eval-Print-Loop. It is a virtual environment where you can run a programming language easily. Node comes with a built-in REPL to run JavaScript code. It is similar to the consoles we use in browsers to run JavaScript code.
To start the Node REPL, you just have to run the command, node, on the command-line. Then, once you write a line of JavaScript code, you can subsequently see its output.
