how-to-build-X.md

How to build X?

In this section we will provide high level overview how to build useful stuff using our system.

Build size tracking

1. Measure size of files that you're interested in (just grab some lib from NPM or use fs.stat ). We treat that value as an artifact.
2. Save value to Storage API for current commit - saveValue method.
3. Get previously saved value for base branch from Storage API - getValue method.
4. Compare these values to get information how build size changed.
5. Use our Report API to report back to github result of comparison - report method.

This is a literally description of what @codechcecks/build-size-watcher does.

Visual regression

1. Obtain screenshots of the current state of the app. Use one of many libraries to make screenshots of storybook or make screenshots during E2E tests.
2. Save directory with screenshots for current commit using Storage API — saveDirectory method.
3. Retrieve previously saved screenshots for base branch from the Storage API — getDirectory method.
4. Compare screenshots using one of many libraries available on NPM and create HTML report describing all changes etc.
5. Upload the HTML report as normal artifact — artifacts are browserable by default — saveDirectory method.
6. Obtain the URL to the uploaded HTML report and attach it to Github PR by using Report API — getArtifactLink method.

Using similar logic you can implement code coverage tracking, performance tracking and basically whatever you want.