Classes Files

Classes

Namespace node.repl

A Read-Eval-Print-Loop (REPL) is available both as a standalone program and easily includable in other programs. REPL provides a way to interactively run JavaScript and see the results. It can be used for debugging, testing, or just trying things out. By executing node without any arguments from the command-line you will be dropped into the REPL. It has simplistic emacs line-editing. 

    mjr:~$ node
    Type '.help' for options.
    > a = [ 1, 2, 3];
    [ 1, 2, 3 ]
    > a.forEach(function (v) {
    ...   console.log(v);
    ...   });
    1
    2
    3
For advanced line-editors, start node with the environmental variable NODENOREADLINE=1. This will start the REPL in canonical terminal settings which will allow you to use with rlwrap. For example, you could add this to your bashrc file: 
    alias node="env NODENOREADLINE=1 rlwrap node"

Method Summary

Method Attributes Method Name and Description
static  
node.repl.start(prompt, source)
Starts a REPL with prompt as the prompt and stream for all I/O.
static  
node.repl.writer(obj, showHidden, depth, colors)

Method Detail

  • static node.repl.start(prompt, source)
    Starts a REPL with prompt as the prompt and stream for all I/O. prompt is optional and defaults to > . stream is optional and defaults to process.stdin. Multiple REPLs may be started against the same running instance of node. Each will share the same global object but will have unique I/O. Here is an example that starts a REPL on stdin, a Unix socket, and a TCP socket: 
        var net = require("net"),
        repl = require("repl");

    connections = 0;

    repl.start("node via stdin> ");

    net.createServer(function (socket) {
      connections += 1;
      repl.start("node via Unix socket> ", socket);
    }).listen("/tmp/node-repl-sock");

    net.createServer(function (socket) {
      connections += 1;
      repl.start("node via TCP socket> ", socket);
    }).listen(5001);
    Running this program from the command line will start a REPL on stdin. Other REPL clients may connect through the Unix socket or TCP socket. telnet is useful for connecting to TCP sockets, and socat can be used to connect to both Unix and TCP sockets. By starting a REPL from a Unix socket-based server instead of stdin, you can connect to a long-running node process without restarting it.
    Parameters:
    {string} prompt
    {string} source
  • static node.repl.writer(obj, showHidden, depth, colors)
    Parameters:
    {Object} obj
    {string} showHidden
    {number} depth
    {string} colors