Point the data at a bucket, and smoke-test every base
The preview can only reach this site's own data, so the two cloud bases fail here on purpose (the buckets are placeholders and do not exist). Use the same loop with your real base: each line should say rows or ok. A 404 means a wrong path, Failed to fetch a wrong host or missing CORS.
Put every part of the Lumen dashboard together, check it against a checklist from Phase 0 to Phase 17, point it at your own cloud bucket by changing one line, build it for production and publish the result. Then see where to go next.
Change the code and press Run (Ctrl+Enter). Predict what will happen first, then break it on purpose and read what changes. Your edits are saved and match the lesson page.
Ready for more? This phase has 5 hands-on exercises with automatic checks.
Practice questions
Write the code in the editor, run it, then open the model answer to compare.
Write the three lines you would add to the README so that a new hire can change the data, run the tests and publish.
Add a post-build script to package.json named check that runs the tests and the build, and explain what it protects against.
Write a cors.json that allows GET only from https://dashboard.example.com, and explain when you would prefer it to *.
Explain it without notes
How do you move the dashboard's data to your own bucket, and what must be set on the bucket?
What does npm run build produce, and how do you check it before publishing?
Why must keys never be in frontend code, and what do you do for private data?
What would you build next, and why?
Console
(nothing was printed)Expected console output
local folder
stations.csv 25 rows
daily.csv 365 rows
station-month.csv 300 rows
hourly-june.csv 720 rows
trips-10k.csv 10000 rows
status.json ok
fleet.json ok
ardenvale.topojson ok
Google Cloud Storage (PLACEHOLDER bucket)
stations.csv TypeError: Failed to fetch
Amazon S3 (PLACEHOLDER bucket)
stations.csv TypeError: Failed to fetch
wrong path on the local base: HTTP 404