Leonardo Devai
11e5f133b5
Pinned 2026 toolchains (Go 1.26, Rust 1.98/edition 2024, Python 3.14 + uv, Node 24, Zig 0.16, NixOS 26.05), postgres 18 / mongo 8, lockfiles built from, non-root runtimes, .dockerignore, per-project LICENSE, READMEs with the git.devai.io clone line, checkout@v7 CI. Security fixes in the legacy Rust APIs (any-password login, self-assigned admin, hard-coded JWT secret), JWT alg/exp/sub enforcement across the blog series, safe markdown links in the frontends, and many smaller bugs — every project was built, run and exercised end to end. Adds scripts/publish.sh + a CI publish job that splits every folder into its own repo at git.devai.io/templates/<folder>. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01128fhuZbgivaSJvtMf4s1G
61 lines
2 KiB
Markdown
61 lines
2 KiB
Markdown
# stopwatch
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A working stopwatch — start, stop, reset and laps — accurate to the hundredth
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of a second. It teaches the one thing most first attempts get wrong about time:
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measure it, don't count it.
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## Run
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Get it: `git clone https://git.devai.io/templates/stopwatch.git`
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Double-click `index.html` — it opens in your browser and works. Nothing to
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install, no build step.
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Or serve it like production:
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```sh
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docker compose up --build
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```
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Then open http://localhost:8080.
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## How it works
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The tempting version adds 10 ms every time a 10 ms timer fires. It drifts:
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timers fire late, and background tabs skip them entirely.
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This one remembers **when** the current run started and subtracts:
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```js
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elapsed + (performance.now() - startTime)
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```
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`performance.now()` is the browser's clock for measuring durations — it only
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moves forward, even if the computer's date and time are adjusted mid-run.
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`setInterval(render, 30)` only decides how often the display repaints; what it
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shows is always computed from the clock, so a late tick can never make it
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wrong. Stopping banks the time so far into `elapsed`; starting again carries on
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from there. A lap is just `format(currentTime())` added to the list.
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Try it: show milliseconds (three digits) instead of hundredths, highlight the
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fastest lap, or start and stop with the space bar.
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## Layout
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```
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index.html the display, three buttons and an empty lap list
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app.js the timing state, format() and the button handlers
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styles.css the look — tabular digits so the numbers don't jiggle
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```
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## Deploy
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Push to your own GitHub repo and the shipped workflow
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(`.github/workflows/ci.yml`) tests the compose stack, publishes the image to
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GHCR, and — once you set the `DEPLOY_HOST` / `DEPLOY_USER` variables and
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`DEPLOY_KEY` secret — deploys it to your server over ssh.
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---
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Part of [devai.io](https://devai.io) — the Web Basics track: HTML, CSS &
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JavaScript, one concept at a time. Next up:
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[color-picker](https://git.devai.io/templates/color-picker).
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