Track package.json and package-lock.json in Git since they’re essential for reproducing the exact development environment. These files allow any developer to install the correct dependency versions.
Exclude node_modules from Git using .gitignore since it contains third-party code that can be downloaded from NPM at any time. Tracking it creates repository bloat and meaningless diffs.
Node_modules contains thousands of files that change with every dependency update, creating noise in your Git history for code you don’t control or need to understand.