Develop Reference

Why does node.js give me a parsing error even when I'm not trying to parse?

I'm somehow getting this error:
UnhandledPromiseRejectionWarning: SyntaxError: Failed to parse value of 607341305994936320votecrate, try passing a raw option to get the raw value
And I don't know why... Could anyone explain what this error means or tell me the error in my code? Thanks!
const express = require('express');
const app = express();
const path = require('path');
const port = 300;
const Database = require("#replit/database")
const db = new Database()
const Topgg = require("#top-gg/sdk")
const topggauth = process.env['topgg']
const webhook = new Topgg.Webhook(topggauth)
app.post("/dblwebhook", webhook.listener(vote => {
const user = vote.user
if (vote.type == 'test'){
console.log(vote)
}
if (vote.type){
const weekend = vote.isWeekend
function weekendcheck() {
if (weekend == "true"){
return 2
}
if (weekend == "false"){
return 1
}
}
var uservotec = (user + "votecrate")
console.log(uservotec)
db.get(uservotec).then(value => {
if (!value){
db.set(uservotec, weekendcheck())
}
if (value){
db.set(uservotec, (weekendcheck() + Number(value)))
}
});
}
}))
app.listen(port, () => console.log('App port online!'));
Thanks! Please note that the vote variable is in json format similar to this:
{
user: '607341305994936320',
type: 'test',
query: '',
bot: '981329232456192100',
isWeekend: 'false',
}

I'm inexperienced with node.js but it seems like you're trying to receive data from the database using an ID, but accidentally passing a varchar to an INT column.
If you replace db.get(uservotec) with db.get(607341305994936320) or db.get('607341305994936320') and don't get any errors, then maybe you should rethink the line var uservotec = (user + "votecrate") because it is concatenating the float/int value with the string "votecrate" resulting in "607341305994936320votecrate" which isn't a valid ID (maybe I'm wrongly assuming but I hope this helps and feel free to ask for a better explanation).

I was able to find an answer. For some reason, I needed to use JSON.stringify on the variable uservotec... Instead of the code in line 28, use this:
var uservotec = JSON.stringify(user + "votecrate")
Alternatively, you could convert the user variable to a javascript object.
var user = JSON.parse(vote.user)
Thank you for everyone's help in helping me find an answer.

How can I change the output of the console in javascript to a file? [duplicate]

Can I configure console.log so that the logs are written on a file instead of being printed in the console?

You could also just overload the default console.log function:
var fs = require('fs');
var util = require('util');
var log_file = fs.createWriteStream(__dirname + '/debug.log', {flags : 'w'});
var log_stdout = process.stdout;
console.log = function(d) { //
log_file.write(util.format(d) + '\n');
log_stdout.write(util.format(d) + '\n');
};
Above example will log to debug.log and stdout.
Edit: See multiparameter version by Clément also on this page.

Update 2013 - This was written around Node v0.2 and v0.4; There are much better utilites now around logging. I highly recommend Winston
Update Late 2013 - We still use winston, but now with a logger library to wrap the functionality around logging of custom objects and formatting. Here is a sample of our logger.js https://gist.github.com/rtgibbons/7354879
Should be as simple as this.
var access = fs.createWriteStream(dir + '/node.access.log', { flags: 'a' })
, error = fs.createWriteStream(dir + '/node.error.log', { flags: 'a' });
// redirect stdout / stderr
proc.stdout.pipe(access);
proc.stderr.pipe(error);

If you are looking for something in production winston is probably the best choice.
If you just want to do dev stuff quickly, output directly to a file (I think this works only for *nix systems):
nohup node simple-server.js > output.log &

I often use many arguments to console.log() and console.error(), so my solution would be:
var fs = require('fs');
var util = require('util');
var logFile = fs.createWriteStream('log.txt', { flags: 'a' });
// Or 'w' to truncate the file every time the process starts.
var logStdout = process.stdout;
console.log = function () {
logFile.write(util.format.apply(null, arguments) + '\n');
logStdout.write(util.format.apply(null, arguments) + '\n');
}
console.error = console.log;

Winston is a very-popular npm-module used for logging.
Here is a how-to.
Install winston in your project as:
npm install winston --save
Here's a configuration ready to use out-of-box that I use frequently in my projects as logger.js under utils.
/**
* Configurations of logger.
*/
const winston = require('winston');
const winstonRotator = require('winston-daily-rotate-file');
const consoleConfig = [
new winston.transports.Console({
'colorize': true
})
];
const createLogger = new winston.Logger({
'transports': consoleConfig
});
const successLogger = createLogger;
successLogger.add(winstonRotator, {
'name': 'access-file',
'level': 'info',
'filename': './logs/access.log',
'json': false,
'datePattern': 'yyyy-MM-dd-',
'prepend': true
});
const errorLogger = createLogger;
errorLogger.add(winstonRotator, {
'name': 'error-file',
'level': 'error',
'filename': './logs/error.log',
'json': false,
'datePattern': 'yyyy-MM-dd-',
'prepend': true
});
module.exports = {
'successlog': successLogger,
'errorlog': errorLogger
};
And then simply import wherever required as this:
const errorLog = require('../util/logger').errorlog;
const successlog = require('../util/logger').successlog;
Then you can log the success as:
successlog.info(`Success Message and variables: ${variable}`);
and Errors as:
errorlog.error(`Error Message : ${error}`);
It also logs all the success-logs and error-logs in a file under logs directory date-wise as you can see here.

const fs = require("fs");
const {keys} = Object;
const {Console} = console;
/**
* Redirect console to a file. Call without path or with false-y
* value to restore original behavior.
* #param {string} [path]
*/
function file(path) {
const con = path ? new Console(fs.createWriteStream(path)) : null;
keys(Console.prototype).forEach(key => {
if (path) {
this[key] = (...args) => con[key](...args);
} else {
delete this[key];
}
});
};
// patch global console object and export
module.exports = console.file = file;
To use it, do something like:
require("./console-file");
console.file("/path/to.log");
console.log("write to file!");
console.error("also write to file!");
console.file(); // go back to writing to stdout

For simple cases, we could redirect the Standard Out (STDOUT) and Standard Error (STDERR) streams directly to a file(say, test.log) using '>' and '2>&1'
Example:
// test.js
(function() {
// Below outputs are sent to Standard Out (STDOUT) stream
console.log("Hello Log");
console.info("Hello Info");
// Below outputs are sent to Standard Error (STDERR) stream
console.error("Hello Error");
console.warn("Hello Warning");
})();
node test.js > test.log 2>&1
As per the POSIX standard, 'input', 'output' and 'error' streams are identified by the positive integer file descriptors (0, 1, 2). i.e., stdin is 0, stdout is 1, and stderr is 2.
Step 1: '2>&1' will redirect from 2 (stderr) to 1 (stdout)
Step 2: '>' will redirect from 1 (stdout) to file (test.log)

If this is for an application, you're probably better off using a logging module. It'll give you more flexibility. Some suggestions.
winston https://github.com/winstonjs/winston
log4js https://github.com/nomiddlename/log4js-node

Straight from nodejs's API docs on Console
const output = fs.createWriteStream('./stdout.log');
const errorOutput = fs.createWriteStream('./stderr.log');
// custom simple logger
const logger = new Console(output, errorOutput);
// use it like console
const count = 5;
logger.log('count: %d', count);
// in stdout.log: count 5

Another solution not mentioned yet is by hooking the Writable streams in process.stdout and process.stderr. This way you don't need to override all the console functions that output to stdout and stderr. This implementation redirects both stdout and stderr to a log file:
var log_file = require('fs').createWriteStream(__dirname + '/log.txt', {flags : 'w'})
function hook_stream(stream, callback) {
var old_write = stream.write
stream.write = (function(write) {
return function(string, encoding, fd) {
write.apply(stream, arguments) // comments this line if you don't want output in the console
callback(string, encoding, fd)
}
})(stream.write)
return function() {
stream.write = old_write
}
}
console.log('a')
console.error('b')
var unhook_stdout = hook_stream(process.stdout, function(string, encoding, fd) {
log_file.write(string, encoding)
})
var unhook_stderr = hook_stream(process.stderr, function(string, encoding, fd) {
log_file.write(string, encoding)
})
console.log('c')
console.error('d')
unhook_stdout()
unhook_stderr()
console.log('e')
console.error('f')
It should print in the console
a
b
c
d
e
f
and in the log file:
c
d
For more info, check this gist.

Overwriting console.log is the way to go. But for it to work in required modules, you also need to export it.
module.exports = console;
To save yourself the trouble of writing log files, rotating and stuff, you might consider using a simple logger module like winston:
// Include the logger module
var winston = require('winston');
// Set up log file. (you can also define size, rotation etc.)
winston.add(winston.transports.File, { filename: 'somefile.log' });
// Overwrite some of the build-in console functions
console.error = winston.error;
console.log = winston.info;
console.info = winston.info;
console.debug = winston.debug;
console.warn = winston.warn;
module.exports = console;

If you're using linux, you can also use output redirection. Not sure about Windows.
node server.js >> file.log 2>> file.log
>> file.log to redirect stdout to the file
2>> file.log to redirect stderr to the file
others use the shorthand &>> for both stdout and stderr but it's not accepted by both my mac and ubuntu :(
extra: > overwrites, while >> appends.
By the way, regarding NodeJS loggers, I use pino + pino-pretty logger

METHOD STDOUT AND STDERR
This approach can help you (I use something similar in my projects) and works for all methods including console.log, console.warn, console.error, console.info
This method write the bytes written in stdout and stderr to file. Is better than changing console.log, console.warn, console.error, console.info methods, because output will be exact the same as this methods output
var fs= require("fs")
var os= require("os")
var HOME= os.homedir()
var stdout_r = fs.createWriteStream(HOME + '/node.stdout.log', { flags: 'a' })
var stderr_r = fs.createWriteStream(HOME + '/node.stderr.log', { flags: 'a' })
var attachToLog= function(std, std_new){
var originalwrite= std.write
std.write= function(data,enc){
try{
var d= data
if(!Buffer.isBuffer(d))
d= Buffer.from(data, (typeof enc === 'string') ? enc : "utf8")
std_new.write.apply(std_new, d)
}catch(e){}
return originalwrite.apply(std, arguments)
}
}
attachToLog(process.stdout, stdout_r)
attachToLog(process.stderr, stderr_r)
// recommended catch error on stdout_r and stderr_r
// stdout_r.on("error", yourfunction)
// stderr_r.on("error", yourfunction)

Adding to the answer above, a lit bit of an expansion to the short and efficient code overriding console.log. Minor additions: set filename with date, wrapper function, also do the original console.logging to keep the console active with the info.
Usage: in the beginning of your code, run setConsoleLogToFile([FILENAME]).
const fs = require("fs"),
util = require('util');
const getPrettyDate = ()=> new Date().toString().replace(":","-").replace(/00\s\(.*\)/, "").replace(` ${new Date().getFullYear()}`, ",").replace(/:\d\d\s/, " ");
module.exports.getPrettyDate = getPrettyDate;
module.exports.setConsoleLogToFile = (filename) => {
const log_file = fs.createWriteStream(`${__dirname}/${filename} - ${getPrettyDate()}.log`, { flags: 'w' }),
log_stdout = process.stdout;
const origConsole = console.log;
console.log = (d) => {
origConsole(d);
log_file.write(util.format(d) + '\n');
log_stdout.write(util.format(d) + '\n');
};
}

Most logger is overkill and does not support the build in console.log correctly. Hence I create console-log-to-file:
import { consoleLogToFile } from "console-log-to-file";
// or `const { consoleLogToFile } = require("console-log-to-file/dist/index.cjs.js")`
consoleLogToFile({
logFilePath: "/log/default.log",
});
// all of your console.log/warn/error/info will work as it does and save to file now.

If you are looking for a solution without modifying any code, here is a simple solution.
It requires pm2, just add it to your node modules and start you app with
pm2 start server.js
And you are done, console.logs are now automatically registered under home/.pm2/logs/server-out.log.

Improve on Andres Riofrio , to handle any number of arguments
var fs = require('fs');
var util = require('util');
var log_file = fs.createWriteStream(__dirname + '/debug.log', {flags : 'w'});
var log_stdout = process.stdout;
console.log = function(...args) {
var output = args.join(' ');
log_file.write(util.format(output) + '\r\n');
log_stdout.write(util.format(output) + '\r\n');
};

You can now use Caterpillar which is a streams based logging system, allowing you to log to it, then pipe the output off to different transforms and locations.
Outputting to a file is as easy as:
var logger = new (require('./').Logger)();
logger.pipe(require('fs').createWriteStream('./debug.log'));
logger.log('your log message');
Complete example on the Caterpillar Website

For future users. #keshavDulal answer doesn't work for latest version. And I couldn't find a proper fix for the issues that are reporting in the latest version 3.3.3.
Anyway I finally fixed it after researching a bit. Here is the solution for winston version 3.3.3
Install winston and winston-daily-rotate-file
npm install winston
npm install winston-daily-rotate-file
Create a new file utils/logger.js
const winston = require('winston');
const winstonRotator = require('winston-daily-rotate-file');
var logger = new winston.createLogger({
transports: [
new (winston.transports.DailyRotateFile)({
name: 'access-file',
level: 'info',
filename: './logs/access.log',
json: false,
datePattern: 'yyyy-MM-DD',
prepend: true,
maxFiles: 10
}),
new (winston.transports.DailyRotateFile)({
name: 'error-file',
level: 'error',
filename: './logs/error.log',
json: false,
datePattern: 'yyyy-MM-DD',
prepend: true,
maxFiles: 10
})
]
});
module.exports = {
logger
};
Then in any file where you want to use logging import the module like
const logger = require('./utils/logger').logger;
Use logger like the following:
logger.info('Info service started');
logger.error('Service crashed');

if you are using forever to keep your node app running, then typing forever list will show you the path to the log file that console.log is writing too

You can use the nodejs Console constructor
const mylog = new console.Console(
fs.createWriteStream("log/logger.log"),
fs.createWriteStream("log/error.log")
);
And then you can use it just like the normal console class, eg:
mylog.log("Ok!"); // Will be written into 'log/logger.log'
mylog.error("Bad!"); // Will be written into 'log/error.log'

You can also have a look at this npm module:
https://www.npmjs.com/package/noogger
noogger
simple and straight forward...

I took on the idea of swapping the output stream to a my stream.
const LogLater = require ('./loglater.js');
var logfile=new LogLater( 'log'+( new Date().toISOString().replace(/[^a-zA-Z0-9]/g,'-') )+'.txt' );
var PassThrough = require('stream').PassThrough;
var myout= new PassThrough();
var wasout=console._stdout;
myout.on('data',(data)=>{logfile.dateline("\r\n"+data);wasout.write(data);});
console._stdout=myout;
var myerr= new PassThrough();
var waserr=console._stderr;
myerr.on('data',(data)=>{logfile.dateline("\r\n"+data);waserr.write(data);});
console._stderr=myerr;
loglater.js:
const fs = require('fs');
function LogLater(filename, noduplicates, interval) {
this.filename = filename || "loglater.txt";
this.arr = [];
this.timeout = false;
this.interval = interval || 1000;
this.noduplicates = noduplicates || true;
this.onsavetimeout_bind = this.onsavetimeout.bind(this);
this.lasttext = "";
process.on('exit',()=>{ if(this.timeout)clearTimeout(this.timeout);this.timeout=false; this.save(); })
}
LogLater.prototype = {
_log: function _log(text) {
this.arr.push(text);
if (!this.timeout) this.timeout = setTimeout(this.onsavetimeout_bind, this.interval);
},
text: function log(text, loglastline) {
if (this.noduplicates) {
if (this.lasttext === text) return;
this.lastline = text;
}
this._log(text);
},
line: function log(text, loglastline) {
if (this.noduplicates) {
if (this.lasttext === text) return;
this.lastline = text;
}
this._log(text + '\r\n');
},
dateline: function dateline(text) {
if (this.noduplicates) {
if (this.lasttext === text) return;
this.lastline = text;
}
this._log(((new Date()).toISOString()) + '\t' + text + '\r\n');
},
onsavetimeout: function onsavetimeout() {
this.timeout = false;
this.save();
},
save: function save() { fs.appendFile(this.filename, this.arr.splice(0, this.arr.length).join(''), function(err) { if (err) console.log(err.stack) }); }
}
module.exports = LogLater;

I just build a pack to do this, hope you like it ;)
https://www.npmjs.com/package/writelog

I for myself simply took the example from winston and added the log(...) method (because winston names it info(..):
Console.js:
"use strict"
// Include the logger module
const winston = require('winston');
const logger = winston.createLogger({
level: 'info',
format: winston.format.json(),
transports: [
//
// - Write to all logs with level `info` and below to `combined.log`
// - Write all logs error (and below) to `error.log`.
//
new winston.transports.File({ filename: 'error.log', level: 'error' }),
new winston.transports.File({ filename: 'combined.log' })
]
});
//
// If we're not in production then log to the `console` with the format:
// `${info.level}: ${info.message} JSON.stringify({ ...rest }) `
//
if (process.env.NODE_ENV !== 'production') {
logger.add(new winston.transports.Console({
format: winston.format.simple()
}));
}
// Add log command
logger.log=logger.info;
module.exports = logger;
Then simply use in your code:
const console = require('Console')
Now you can simply use the normal log functions in your file and it will create a file AND log it to your console (while debugging/developing). Because of if (process.env.NODE_ENV !== 'production') { (in case you want it also in production)...

Create a utils/logger.js file with:
var fs = require('fs');
var util = require('util');
var log_file = fs.createWriteStream(__dirname + '/../logs/server.log', { flags: 'w' });
var log_stdout = process.stdout;
console.log = function () { //
[...arguments].forEach(element => {
log_file.write(util.format(element) + '\n');
log_stdout.write(util.format(element) + '\n');
});
};
module.exports = {
console
}
Include the logger.js file from any file where you want to console.log like:
const console = require('./utils/logger').console;
Create a logs folder and create an empty server.log file in it and run your app :)

Rudy Huynh's solution worked really well for me. I added a little bit to have it spit out files with today's date and time.
var dateNow = new Date();
var timeNow = dateNow.getHours() + '-' + dateNow.getMinutes();
var logPath = "log/" + dateNow.toDateString() + ' -' + ' Start Time - ' + timeNow + ".log"
consoleLogToFile({
logFilePath: logPath
});
It's not very elegant but this way it'll save different, easy to read, log files instead of just updating the same "default.log" file.

Based on multiparameter version by Clément, just without color codes for the text file
var fs = require('fs');
var util = require('util');
var logFile = fs.createWriteStream('log.txt', { flags: 'a' });
// Or 'w' to truncate the file every time the process starts.
var logStdout = process.stdout;
console.log = function () {
// Storing without color codes
logFile.write(util.format.apply(null,arguments).replace(/\033\[[0-9;]*m/g,"") + '\n');
// Display normally, with colors to Stdout
logStdout.write(util.format.apply(null, arguments) + '\n');
}
Note: Answering since I couldn't comment

socket.io code organizing and timing ES6

i have an experimental app that is pretty simple, you click a display button and an image appears in real time to all clients, utilizing socket.io. now it does work for the most part. however i had an issue (my original question here: socket.io emit on connect) with an event not happening when the client connected, but i have resolved it with the help of this thread: socket.emit on sever side is ignored after connection?.
basically, my 'new-client-append event' retrieves data (html in the form of a string) so that when a new client connects, it shows the same data that current clients see (similar to connecting to a chat room and being able to see all chat history). i had to reorganize my code so my 'new-client-append' event would take place, and i can get it to work if i put data in manually. my new issue is now that i have had to reorganize my code, my 'new-client-append' event is dependent on a variable i set within the class, so it is no longer recognizable. i'm relatively new to JS, how can i get my variable to be recognized and why is this happening? i had tried moving the event in different places of my code with no luck. it is the this.mainContainer variable.
CLIENT
import $ from 'jquery';
import SaveInput from './SaveInput';
import io from 'socket.io-client';
// make connection
const socket = io.connect('localhost:3000');
**socket.on('new-client-append', (data) => {
console.log('NEW CLIENT ENTERED');
console.log('on new-client-clone ' + JSON.stringify(data));
this.mainContainer.append(data);
});**
socket.on('connect_error', function(){
console.log('fail');
});
class Display extends SaveInput {
constructor(){
this.mainContainer = $('.main-container');
this.pGrid = $('.pic-grid-container');
this.display = $('#btn-display');
this.buttons();
}
buttons (){
// click buttons
this.display.click(this.displayEls.bind(this));
//display images
displayEls() {
let img = 'https://secure.gravatar.com/avatar/22f38e0216f57af53a1776fb2a72c436?s=60&d=wavatar&r=g';
let $picContainer = $('<div class="picture-frame"></div>');
let $newImg = $('<img>');
// clone pic-grid-container
let htmlClone = this.pGrid.clone();
let stringClone = htmlClone.html();
// EMIT
//send image url
socket.emit('client-image', {
image: img
});
// send dom clone to server
socket.emit('new-client-append', {
clone: stringClone
});
// LISTEN
// append image in real time
socket.on('client-image', (data) => {
let foo = data.image.toString();
$newImg.attr('src', foo);
// console.log(data);
// console.log(foo);
$newImg.appendTo($picContainer);
this.pGrid.append($picContainer);
// console.log('html clone ' + JSON.stringify(htmlClone));
// console.log('string clone ' + stringClone);
});
}
export default Display;
SERVER
const express = require('express');
const socketIO = require('socket.io');
const http = require('http');
// app set up
const app = express();
const server = http.Server(app);
// const = new socket(server);
let port = process.env.PORT || 3000;
// static files
app.use(express.static('app'));
// socket setup & pass SERVER
const io = new socketIO(server);
let jqueryImage;
// on client connect
io.on('connection', (socket) => {
console.log('client has entered...');
socket.emit('new-client-append', jqueryImage);
// events
socket.on('client-image', function(data){
console.log('SERVER ' + data.image);
io.sockets.emit('client-image', data);
});
socket.on('new-client-append', function(data){
jqueryImage = data.clone;
console.log('jqueryImage ' + JSON.stringify(jqueryImage));
});
// errors
io.on('error', function (err) {
console.log(err);
});
io.on('connect_error', function(){
console.log('fail');
});
});
server.listen(port, () => {
console.log('server running....');
});
UPDATE
added suggested code, calling the maincontainer from the display object. but it is saying that it is not defined.
socket.on('new-client-append', (data) => {
console.log('NEW CLIENT ENTERED');
console.log('on new-client-clone ' + JSON.stringify(data));
**display.mainContainer.append(data);**
});
file where i create the objects
import SaveInput from './modules/SaveInput';
import Display from './modules/Display';
const saveInput = new SaveInput();
const display = new Display ();

Your socket.on function has
this.mainContainer.append(data);
This implies that you've attached a mainContainer property to the socket object. Because you've not done this, but rather declared it inside your Display (sub)class, it's attached to the Display object you created.. I can't seem to find it, but somewhere, wherever this script is required there is a
variable = new Display();
You must call this mainContainer object by it's name. Find that code that initiates the Display object and then use
theVarNameYouFound.mainContainer.append(thatThing);

typeerror undefined is not a function in node js

I have a simple form which gives me below error.
TypeError: undefined is not a function on line no 20. plese help me
var path = require('path')
var funcs = require('./funcs')
var encodeName = funcs.encodName
var session = {
username: process.argv[2],
lastMessageHash: process.argv[3]
}
if (!session.username || !session.lastMessageHash) {
console.log('Usage: node index.js <username> <hash>')
process.exit(0)
}
// 1. load the database
var dbFile = path.join(__dirname, 'db', 'index.json')
funcs.loadDb(dbFile, function (err, db) {
// 2. encode the name
var encoded = encodeName(session.usrename) // error line no 20
// 3. find the user's inbox
var inbox = funcs.findInbox(db, encoded)
// 4. find the next message
var nextMessage = funcs.findNextMessage(inbox, session.lastMessageHash)
// 5. print out the message.
// Paste the console output into the "Solution" field and you're done!
console.log(nextMessage)
})
I am working on simple page with database conncection on my node js project. i am newbe in nodejs.

I cannot say for sure why it's not working since I don't know the content of ./funcs, but there are typos in the line 3 and line 20, so it may be that because of the typo it doesn't find the proper function. You better check your code more carefully.

Using node.js's prompt for user input? [duplicate]

This question already has answers here:
Get user input through Node.js console
(6 answers)
Closed last month.
I'm working on a JS project running with node.js and I can't figure out how to get the prompt to work correctly for user input. I installed it from npm, followed the steps and I can get the program to prompt for user input but I can't store the result in a variable.
What I want is to prompt the user for his next move (up,down,left or right) every turn and use the result. I tried making a global move variable and affecting it in the prompt section, but it doesn't seem to work.
var Moving = function(maxMoves){
for(var n=maxMoves; n>0;){
var move;
var l;
//This would prompt for a direction (up,down,left,right)
move = prompt();
//And this would prompt for the number of tiles to advance;
l = prompt();
Direction(move,l);
n-=l;
}
};

Using require('prompt') or require('readline') are both good, easy ways to do this, but I wanted to find THE EASIEST WAY, and I didn't care about whether it is synchronous or asynchronous. Finding it took me longer than it should have, so maybe I can save people some time if they read this before digging any further.
Here you go:
# npm install readline-sync
var readline = require('readline-sync');
var name = readline.question("What is your name?");
console.log("Hi " + name + ", nice to meet you.");
Disclaimer: I am just spreading the word, here are my sources:
https://teamtreehouse.com/community/how-to-get-input-in-the-console-in-nodejs
How to take in text input from a keyboard and store it into a variable?

When you say "installed it from npm" I'm assuming you're referring to the prompt module from flatiron.
From their docs, as with most Node things, it looks like it exposes an asynchronous function, so you'll handle input inside the prompt callback:
var prompt = require('prompt');
//
// Start the prompt
//
prompt.start();
//
// Get two properties from the user: username and email
//
prompt.get(['username', 'email'], function (err, result) {
//
// Log the results.
//
console.log('Command-line input received:');
console.log(' username: ' + result.username);
console.log(' email: ' + result.email);
});
Storing it in a variable would be no different than accessing it from the result object above, but realize that since it's async it'll only be reliable available inside that callback.

you can use two packages readline and prompt
Here's a simple example with readline package https://nodejs.org/en/knowledge/command-line/how-to-prompt-for-command-line-input/
const readline = require('readline');
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout
});
rl.question('What is your name ? ', function (name) {
rl.question('Where do you live ? ', function (country) {
console.log(`${name}, is a citizen of ${country}`);
rl.close();
});
});
rl.on('close', function () {
console.log('\nBYE BYE !!!');
process.exit(0);
});
Here is an another example with prompt package. https://www.npmjs.com/package/prompt
const prompt = require('prompt');
prompt.start();
prompt.get(['username','email'], function (err, result) {
console.log('Command-line input received:');
console.log(' username: ' + result.username);
console.log(' email: ' + result.email);
});

inquirer module has a prompt function.
Use
const { prompt } = require('inquirer');
prompt([array] | object | string ')