nodejs cannot see installed mysql module

Question

I'm trying to install the mysql module for nodejs using npm. I'm using the windows subsystem for linux to do this. I've successfully installed using:

sudo npm install -g mysql

My console returns:

+ mysql@2.16.0
added 11 packages from 15 contributors in 5.779s

However, when importing the module using:

const mysql = require("mysql");

I receive the error:

module.js:550
    throw err;
    ^

Error: Cannot find module 'mysql'
    at Function.Module._resolveFilename (module.js:548:15)
    at Function.Module._load (module.js:475:25)
    at Module.require (module.js:597:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/mnt/c/Users/alesi/Documents/coding/Web/Portfolio/src/servers/server.js:7:15)
    at Module._compile (module.js:653:30)
    at Object.Module._extensions..js (module.js:664:10)
    at Module.load (module.js:566:32)
    at tryModuleLoad (module.js:506:12)
    at Function.Module._load (module.js:498:3)

Other modules such as querystring and nodemailer work just fine. Any ideas?

You're installing globally and not in the actually project node_modules. Need to `npm install --save mysql`. That should install to your project's node_modules and write to package.json as a dependency. — Isaac Vidrine, Feb 27 '19 at 16:58
Cheers that has solved the problem. Could I ask why I can't do this globally as with other packages? Thus far I have installed other modules globally as the documentation suggests this should also work. — Alesi Rowland, Feb 27 '19 at 17:08

Isaac Vidrine · Answer 1 · 2019-02-27T18:19:37.060

When you install a package globally, the package is usually installed in %USERPROFILE%\AppData\Roaming\npm\node_module on windows or /usr/local/lib/node_modules in unix systems. See this post.

Now in your project, when you require() something, it is looking to the current directory's node_modules folder. Because you installed the package globally, it does not exist in the project.

Running this will download the package to your project's node_modules folder, instead of global node_modules. --save will also write it as a dependency to package.json

npm install --save mysql

In my experience, global packages seem to be used for CLI's or running scripts from command prompt, and not for using in code.

nodejs cannot see installed mysql module

1 Answers1