I'm trying to add "last updated" time to my blog on Gatsby.

Timeline

• Day 1. Install Gulp
• Day 2. Recursively get a list of files where date is needed
• Day 3. I don't know about streams in Nodejs. How to use through2? 🤯
• Day 4. I don't want to read about through2, its API is irrational 🙊
• Day 5. No
• Day 6. Nope
• Day 7. Finished with the search bar
• Day 8. The light came, I understand how to use secrets in GitHub's actions
• Day 9. Updated Gatsby to 4. It broke GraphQL queries with childImageSharp. Fixed by undocumented feature mentioned in a comment on Gatsby's issue tracker.
• Day 10. Back to Gulp. I'm getting file contents 🥳. Am I following tutorials? No, I'm adopting code from other plugins 🤠
• Day 11. Crafted 2 git log commands to get date when file was initially published and last modification time. The result from child process comes in callback, so I will need to figure out how to wrap it in a Promise and return this thing from Gulp's task.
• Day 12. I wanted to report here that I was consumed by Dapp investigation and did 0 progress, but then opened my draft notes from the yesterday and did small refactoring. I still disagree with the statement:

"Streams are node's best and most misunderstood idea"

• Day 13 - Day 20. No progress whatsoever.
• Day 21. Done. Final gulpfile.js file

Takeout

Just for fun and educational purposes I tried to avoid new dependencies. I could use gulp-git, gulp-replace or gulp-inject-string modules, but instead I studied their code and used only bare minimum for my needs.

I learned about /d flag in RegEx and a little about Transform.

The turning point happened when I realized that transform inside transform is not going to work, and that pipe() doesn't take gulp's task as an argument. Sounds silly now, but lack of tutorials and dynamic types were telling me: why not? 👿

Reference

• work with streams https://github.com/gulpjs/gulp/blob/master/docs/writing-a-plugin/dealing-with-streams.md
• no use of through2, use Transform https://github.com/lazd/gulp-replace/blob/master/index.js
• get file content https://github.com/eugeneware/replacestream/blob/master/index.js
• good example https://github.com/sindresorhus/gulp-filter/blob/main/index.js
• git: last modified time https://stackoverflow.com/questions/4784575/how-do-i-find-the-most-recent-git-commit-that-modified-a-file
• git: first published time https://stackoverflow.com/questions/11533199/git-find-commit-where-file-was-added
• git log https://git-scm.com/docs/git-log
• gulp git https://github.com/stevelacy/gulp-git/blob/master/lib/exec.js
• file content manipulation https://github.com/mikehazell/gulp-inject-string/blob/master/index.js