Node.js REPL

Node.js comes with node shell to write and print commands, it is called REPL (Read-Eval-Print-Loop). REPL provides a computer environment like a window console or a UNIX/Linux shell, where we can execute Node.js/Javascript code. It reads JavaScript code the user enters and evaluates the result by interpreting the line of code and prints the result to the screen.

REPL stands for

Read - Read the user's input and store in memory.
Eval - Evaluates the data structure.
Print - Prints the result.
Loop - Loops the given command until someone press ctrl+c.

Start REPL Window

To start REPL window, open cmd and simply type node or go to start and search for Node.js icon and click to launch the REPL window. If you have node installed, then you also have the Node.js REPL.

$ node

This results in the REPL prompt:

$ >

Expression Continuity

Node.js REPL automatically check for multiline expression. For multiline expression, just press has entered to write in next line. REPL displays three dots (...). This means we can write next line code here.

REPL Commands

ctrl+c - Used to terminate the current command.

ctrl+c double - Used to terminate the Node REPL.

ctrl+d - Used to terminate the Node REPL.

break - Used to get out of the multiline expression.

help - Used to list all commands.

load - Used to load file contents in current REPL Session.

save - Used to save the current REPL session to a file.

tab Keys - list of current commands.