| 1 | # apps/web |
| 2 | |
| 3 | ## A part that fails stays in its part |
| 4 | |
| 5 | Every page is built so one failed read or one broken card never takes the |
| 6 | page down. Follow this on any page you add or change; older pages are |
| 7 | brought up to it as they are worked on. |
| 8 | |
| 9 | - **What a page is about is read strictly.** The pull request on its page, |
| 10 | the settings being edited, anything that decides access or a redirect: |
| 11 | if that fails, the page fails, inside its frame (routes/page-boundary.tsx). |
| 12 | - **Everything beside it is a part.** Read it through |
| 13 | `part(promise, "What it is")` (app/lib/partial.ts). It gives the value, or |
| 14 | `Failed` when the service did not answer or answered with a 5xx. A 404 or |
| 15 | a refusal (`{ ok: false }`) is an answer, not a failure: read it as before. |
| 16 | - **A failed part says so in its own place**, the way a form says what is |
| 17 | wrong beside the field: `<Unavailable what="…" />` |
| 18 | (app/components/boundary.tsx; `compact` in a sidebar or small slot), |
| 19 | under the card's heading. Never let a failure read as an empty or false |
| 20 | state ("No deployments yet", "Checks are off"). |
| 21 | - **A form whose data failed is not shown.** Show Unavailable instead, so |
| 22 | nothing is saved over values that were never read. |
| 23 | - **Quiet fallback only for what nobody would miss** (a decoration, a |
| 24 | suggestion the server checks again): `orElse(await part(…), fallback)`, |
| 25 | with a comment saying why. |
| 26 | - **A complex card sits in `<Boundary what="…">`**, so an error while |
| 27 | drawing stays in the card. `Panel` does this already. |
| 28 | - **A streamed promise never rejects into an `<Await>` without an |
| 29 | `errorElement`**: resolve it through `part`, or give it one. |
| 30 | |
| 31 | Network blips are handled once for every page (app/lib/resilient-fetch.ts, |
| 32 | components/connection-toast.tsx); the root error page is the last resort. |