How Do I Select Git Ignore Node. Js After I've Already Created a Repository?

If .gitignore not already created just add a new file .gitignore with below content in your project directory. If the file already created you can add below content in existing file.

# Dependency directories
node_modules/

# Optional npm cache directory
.npm

# dotenv environment variables file
.env

You can find more suitable ignores here Node.gitignore. After creating a new file run the following commands for update on upstream.

git rm -r --cached . 
git add .
git commit -m 'Removed all files that are in the .gitignore' 
git push origin master

This will help you to solve your problem.

You can always create a new .gitignore file manually if it is not already created. If a file is existing, you can edit .gitignore file and add it into your repository.