Nodejs

Installed Versions

Used nvm-windows to handle multiple versions of node (needed for [Redwood.js]({% link _notes/redwood.md %}))

nvm use [version]

• 18.19.0
• 20.10.0

Errors

Fix the upstream dependency conflict, or retry npm ERR! this command with —force or —legacy-peer-deps

This is a package conflict, you can pin the version to the specified version, or run with the flags to suppess the warnings. This may cause unintended results.

Build A CLI

1. Create a folder for your cli

2. Run npm init

   • set entry point to bin/index.js
   • to use esm modules (import instead of require) add to your package.json

   "type": "module"Copy

3. Create directory and file bin/index.js

   • index.js will contain the code to be executed

4. At the top of index.js add:

   # !/usr/bin/env nodeCopy

   #!/usr/bin/env node is an instance of a shebang line: the very first line in an executable plain-text file on Unix-like platforms that tells the system what interpreter to pass that file to for execution, via the command line following the magic #! prefix (called shebang).

5. Add a main function and invoke it

   function main() {
     // code
   }
   
   main();Copy

   or use an IFFE (Imediately Invoked Function Expression)

   (function() {
     //code
   })();Copy

Files

Go to nodejs file system docs

Import the file module

import fs from "node:fs";Copy

Writing a file

At the most rudimentary level, writeFile() takes 4 arguments:

• output file name
• file data
• encoding
• callback function that recieves (err, written, string)

    fs.writeFile('note.md', "Hello world!", 'utf-8', (err) => {
      if (err) {
        console.log('err: ', err);
      }
    });Copy