Develop Reference

Getting Node Module Error (Cannot find module)

I am learning the Automated tests by using selenium web driver + Javascript and node.js.
Everything is working fine when I ran that script.js from the Visual Studio code terminal(by using node main.js)
Problem
I want to schedule this script in the scheduler which automatically tests the login functionality. But when I try to run it from the task scheduler then it gives Error: Cannot find module
Does anybody know how to get rid of this.

To fix Cannot find module errors, install the modules properly by running a npm install command in the appropriate directory as your project's app. ... or delete the node_modules folder and package-lock. json file and re-install it again using the npm install command.
rm -rf node_modules package-lock.json

react-native, bundling failed

I am new to react-native and have found an error that makes absolutely no sense to me.
I am trying to include a calendar library: https://github.com/wix/react-native-calendars
I have included the dependency for that library in my package.json file and run npm install
The project was running fine and as expected. I have simply added one line of code to the project:
import { Calendar, CalendarList, Agenda } from 'react-native-calendars';
Nothing else. However now I am getting a red error message when the app loads on device and this is what my console is saying:
error: bundling failed: Error: While trying to resolve module xdate
from file
/Users/Alex/Documents/workspace/mobile/node_modules/react-native-calendars/src/index.js,
the package
/Users/Alex/Documents/workspace/mobile/node_modules/xdate/package.json
was successfully found. However, this package itself specifies a
main module field that could not be resolved
(/Users/Alex/Documents/workspace/mobile/node_modules/xdate/src/xdate.js.
Indeed, none of these files exist:
*
/Users/Alex/Documents/workspace/mobile/node_modules/xdate/src/xdate.js(.native||.ios.js|.native.js|.js|.ios.json|.native.json|.json)
*
/Users/Alex/Documents/workspace/mobile/node_modules/xdate/src/xdate.js/index(.native||.ios.js|.native.js|.js|.ios.json|.native.json|.json)
at ResolutionRequest.resolveDependency (/Users/Alex/Documents/workspace/mobile/node_modules/metro/src/node-haste/DependencyGraph/ResolutionRequest.js:103:15)
at DependencyGraph.resolveDependency (/Users/Alex/Documents/workspace/mobile/node_modules/metro/src/node-haste/DependencyGraph.js:272:4579)
at dependencies.map.relativePath (/Users/Alex/Documents/workspace/mobile/node_modules/metro/src/DeltaBundler/traverseDependencies.js:376:19)
at Array.map ()
at resolveDependencies (/Users/Alex/Documents/workspace/mobile/node_modules/metro/src/DeltaBundler/traverseDependencies.js:374:16)
at /Users/Alex/Documents/workspace/mobile/node_modules/metro/src/DeltaBundler/traverseDependencies.js:212:33
at Generator.next ()
at step (/Users/Alex/Documents/workspace/mobile/node_modules/metro/src/DeltaBundler/traverseDependencies.js:297:313)
at /Users/Alex/Documents/workspace/mobile/node_modules/metro/src/DeltaBundler/traverseDependencies.js:297:473
at
However I have checked in the directory and in fact /Users/Alex/Documents/workspace/mobile/node_modules/xdate/src/xdate.js does exist. However I do not see any of this part: (.native||.ios.js|.native.js|.js|.ios.json|.native.json|.json)`
As to how /Users/Alex/Documents/workspace/mobile/node_modules/xdate/src/xdate.js/index can exist, that doesn't make sense because xdate.js is not a directory.
Any help?

It Usually happens if you try to install a module while your packager is open.
Try to delete node_modules folder and close the packager.
Then reinstall everything by npm install in your project directory.

First close your JavaScript bundler (Metro bundler in my case) and restart the application. This will create fresh dependency graph. This should solve the issue.

Just restart the bundler - no need to delete the Node Modules folder
I came across this issue when adding and using react-native-elements when using VS Code and Android Studio emulator on Linux Mint
In VS Code I had a terminal running Expo with Metro Bundler via 'npm start' command. After installing the react-native-elements in the folder (using 'npm install --save react-native-elements') and adding the import into the .js file I got the "However, this package itself specifies a main module field that could not be resolved" error.
In my case, this just involved a ^C in the terminal session to stop the Metro bundler and then running 'npm start' again. There was no need to delete the node modules folder at all.

If you're still getting the error even after deleting the ./node_modules folder and running npm install again, try doing the install with the --update-binary flag, i.e npm install --update-binary. This should clear out and rebuild any previously built packages on your machine.

Please don't delete the node modules folder.
The bundler has least to deal with node modules folder.
Instead close all the terminals. If using VS-code close that also.
Close all the local host server ports and if possible restart the system.
This might solve the issue.

If anyone have same issue, and remove node_module not working. Then you can try remove all node_module, package lock and using yarn to install node_module instead npm. Hope this help

None of the solutions above helped me except for restarting my MacBook. Wasted 30 minutes trying to fix this issue as I couldn't believe restarting my computer could be a solution.

Error: Module did not self-register.

Server: Ubuntu server 14.04
Node: v4.2.6 LTS
npm: 1.3.10
I pullled my colleage's work from git remote. He made the node_modules as .gitignore. So I have to npm install the modules.
But after a successful install of npm. when I try to start the project using mocha. It remind me of a module didn't self-register
The error comes from the module of Bcrypt.
at bindings (/base_dir/node_modules/bcrypt/node_modules/bindings/bindings.js:76:44)
I don't want to downgrade my node to 0.10, because, I can't use JS promise in that version. Somehow, JS promise is a must in my work

This problem happens mostly because you copied/cloned the repository from somewhere else, but some modules for nodeJS should be installed/registered locally on your machine, during which the happens the build process(maybe some native language like C).
and be noted that the node_modules folder should not be staged for versioning. and should be ignored by versioning tool. and the one who is trying to clone this package should build / install firstly.
I find the answer to this problem.
But plz don't devoted this just because you want.
I upgrade the NPM using
npm install npm -g.
after that, delete the node_modules folder,
then,
npm install
Everything will be good.

I had this issue while setting up my Cypress project.
After trying to delete and then reinstalling all the node-modules and upgrading everything I found out the issue was caused because Cypress uses node from its bundle version by default (which was version 8.0 in my case) , whilst the package I wanted to use required the node version to be 10 or higher.
I did have node 12.0 installed on my machine but since cypress was not using that I had to add the line shown below in the settings file (cypress.json) to set the value for 'nodeVersion' to 'system', this way you are telling cypress explicitly to use the node version installed on your machine.
Add this line to your settings file:
**"nodeVersion": "system"**

Not Getting $ in command prompt in Node.Js

My NodeJs is working fine but i have an issue I'm not seeing $ in the prompt as most example point.
Another issue is when i put sudo I dont get anything.Things I have tried are the following
$ sudo npm install npm -g
/usr/bin/npm -> /usr/lib/node_modules/npm/bin/npm-cli.js
npm#2.7.1 /usr/lib/node_modules/npm
given on the following Website
http://www.tutorialspoint.com/nodejs/nodejs_npm.htm
Apologies am very new to Node.JS.Please help

I'm going to explain this in terms familiar to MS windows.
$ npm --version
^ dollar sign is the same as "C:\" in windows.
It just means "from here..." in the most basic terms I can use.
You don't need the dollar sign for anything in that tutorial.
"sudo" means "elevate to an administrator level" similar to opening a command line terminal "in administrator mode." But for Linux (Ubuntu and Mac as *NIX) systems.
--version can be called as "-v" most of the time and means "for the thing I've named before, in this case "npm" show me the version.
Once you've installed NodeJS it comes with a "package manager" called NPM. The best way to relate this to windows is by considering it a command line version of an "installation" that installs different programs as you tell it to with different options.
"npm install -g" means "Hey NPM! Install to EVERYWHERE(call from command line/terminal/bash) the thing I Tell you next. "npm install -g express" for example, means hey NPM, install "expressJS" globally, so I can use the terminal to write commands(micro apps) from the expressJS I just installed with node.
"npm install --save" means hey, install this microapp, but ONLY let me use it in THIS EXACT FOLDER I'm in, and let anyone else that is in this folder know they need to install it to use this application I'm making.
"npm init" Is actually the FIRST thing you should do in any node project folder. It creates the "package.json" file in the current directory, and it will define the folder you're in as the folder to start installing stuff you "npm install" to the "node_modules" folder that will show in the folder you're currently in.
If you want to tinker with NodeJS code, and you don't want to tamper with your local machine and install all kinds of stuff you're not totally sure about yet you can use "REPL.it" (https://repl.it/languages/nodejs) the white window on the right is treated like a file you'd run in node. The dark window on the right is an actual NODE TERMINAL that you can run nodejs commands/code in directly.
There's one other good resources in general and that is here (https://devdocs.io/) it's called "Devdocs" and it has Node, npm, and express code examples, clean explanations, and examples that you can download directly to your local machine.
I hope that gets you moving with NodeJS. It's hard to understand, but with a bit of try and fail you'll start to try more and fail less. Cheers!

NodeJs - FTP not working: "npm-shrinkwrap.json is not provided"

I have got a Nodejs app on AppFog and want to connect to a ftp-server with this.
I did install it with npm install ftp using "Ruby Command Prompt"
This is the only code line:
var FTPClient = require('ftp');
Trying to start the app, it throws an error:
Skipping npm-support: npm-shrinkwrap.json is not provided
Which kind of server should I use or what's the problem?
Still doesn't start:
Starting Application 'test007': .
Error: Application [test007] failed to start, logs information below.
====> /logs/staging.log <====
# Logfile created on 2013-03-09 10:37:09 +0000 by logger.rb/25413
Installing dependencies. Node version 0.8.14
Installing ftp#0.2.9 from local path
Installing xregexp#2.0.0 from local path
Installing node#0.0.0 from local path
Installing nodejs#0.0.1 from local path
But no error is shown.
Thanks in advance

The quick fix is to type npm shrinkwrap, which will provide an npm-shrinkwrap file.
A shrinkwrap file fixes the exact versions of your dependencies, and the exact version of their dependencies, and so on. Without it, each usage of npm install could install different versions of the packages -- sometimes, just different bugfix versions (1.4.2 vs 1.4.3), but sometimes much greater differences. There's no guarantee that your code will work with different dependency versions (in fact it is not uncommon to break), so shrinkwrapping is a great idea for any production-level code.
If you want to 'unshrinkwrap', just delete the npm-shrinkwrap.json. You can re-shrinkwrap at any point.