Creating a pipeline that automatically builds and tests the application on every commit.
Now we'll create the Continuous Integration (CI) part of the pipeline for our Node.js application. We'll use a tool like GitHub Actions or GitLab CI/CD and define the workflow in a YAML file. This pipeline will be triggered automatically on every push to the repository. The first stage of the pipeline will be the 'build' stage. In this stage, the CI runner will check out the source code from the repository. Then, it will execute `npm install` (or `npm ci` for a cleaner install) to download all the project dependencies defined in `package.json`. The next crucial stage is 'test'. Here, the pipeline will run our automated tests by executing a command like `npm test`. This step is vital for ensuring that the new code changes haven't introduced any regressions or broken existing functionality. If any of the tests fail, the pipeline will fail, and the developer will be notified immediately. This provides a fast feedback loop, allowing for quick fixes. As an optional but recommended step, we can add a 'lint' job to this stage. This job will run a tool like ESLint to check the code for style issues and potential bugs, further improving code quality. By the end of this CI pipeline, we will have an automated process that verifies the integrity and quality of our code on every single commit.