continuous-integration-continuous-deployment

Continuous Integration/Continuous Deployment (CI/CD) with TypeScript:

• CI/CD Pipeline Basics:

  Understand the basics of CI/CD pipelines. CI involves automated testing and building of your code with every commit, while CD ensures that every change that passes CI is automatically deployed to your production environment.

• TypeScript Compilation Step:

  Include a compilation step in your CI pipeline to check for TypeScript type errors. This should fail the build if any type checking errors are present.

• Linting in CI:

  Integrate ESLint or TSLint in your CI pipeline to ensure code quality and style consistency. Your build should fail on linting errors.

• Testing:

  Ensure that your CI pipeline runs all automated tests - unit, integration, and end-to-end tests. Use a test runner that supports TypeScript out of the box or is properly configured to handle TypeScript files.

• Code Coverage:

  Use a tool that supports TypeScript to track code coverage and enforce coverage thresholds. Coverage reports should be accessible for each build.

• Artifact Creation:

  Set up your CI pipeline to package your TypeScript application into a deployable artifact, like a Docker container, after successful compilation and testing.

• Automated Deployment:

  Implement automated deployment in your CD pipeline. Successful builds should trigger deployment scripts that update your production environment.

• Environment Variables:

  Manage environment-specific configurations using environment variables in your CI/CD pipeline, avoiding hardcoded values in your TypeScript code.

• Build Matrix:

  Use a build matrix in your CI system to test your TypeScript application across different environments, Node.js versions, or operating systems.

• Caching:

  Configure caching in your CI pipeline for node_modules to speed up the build process, but ensure that it doesn't lead to inconsistencies in dependency resolution.

• Rollback Strategies:

  Have a rollback strategy in place for when a deployment fails or introduces a critical bug. Your CD system should support quick rollbacks to the last known good state.

• Branching Strategy:

  Define a clear branching strategy (like Gitflow) that your CI/CD pipelines can support for different environments (development, staging, production).

• Monorepo Considerations:

  If working within a monorepo, your CI/CD pipeline should be optimized to only build and deploy the projects that have changed.

• Preview Environments:

  Set up dynamic preview environments for pull requests using your CD tools. This allows for real-world testing of changes in isolation before merging to main branches.

• Security Checks:

  Integrate security checks into your CI pipeline. This should include scanning dependencies for known vulnerabilities with tools like npm audit or snyk.

• Docker and TypeScript:

  When using Docker, ensure your images are optimized for TypeScript by including only the transpiled JavaScript and necessary production dependencies in the final image.