Node.js REPL (Read-Eval-Print-Loop) is an interactive shell that processes Node.js expressions. The shell reads JavaScript code the user enters, evaluates the result of interpreting the line of code, prints the result to the user, and loops until the user signals to quit.
The REPL shell allows quick testing of JavaScript/Node.js code and algorithms, similar to how one might use the console in a web browser’s developer tools. This is especially useful for learning JavaScript and for incremental development.