変更を判断する前に比較を読んでください

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>GitTree Features — course demo</title>
  <link rel="stylesheet" href="styles.css">
</head>
<body>
  <header class="site-header">
    <a href="#main">GitTree Features</a>
  </header>
  <main id="main">
    <section class="hero" aria-labelledby="hero-title">
      <p class="eyebrow">GitTree Learn demo project</p>
      <h1 id="hero-title">Understand every change.</h1>
      <p id="hero-copy">Choose one change, then check what Git saved.</p>
    </section>
    <section class="features" aria-labelledby="features-title">
      <h2 id="features-title">Follow your work</h2>
      <div class="cards">
        <article class="feature-card">
          <h3>History</h3>
          <p>Read commits and branches together.</p>
        </article>
        <article class="feature-card">
          <h3>Changes</h3>
          <p>Review the exact content selected for a commit.</p>
        </article>
        <article class="feature-card">
          <h3>Recovery</h3>
          <p>Inspect the scope of a recovery point before using it.</p>
        </article>
      </div>
    </section>
  </main>
  <footer><p>Built by a fictional team for GitTree Learn.</p></footer>
  <script type="module" src="site.js"></script>
</body>
</html>

:root {
  color-scheme: light;
  --page: #f7f8fa;
  --surface: #ffffff;
  --text: #17212e;
  --link: #154ab5;
  --line: #bac4d0;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--page);
  color: var(--text);
  font: 1rem/1.6 system-ui, sans-serif;
}

a {
  color: var(--link);
}

.site-header,
main,
footer {
  width: min(68rem, 100% - 2rem);
  margin-inline: auto;
}

.site-header {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 1rem;
}

.hero {
  max-width: 44rem;
  padding-block: 3rem;
}

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  line-height: 1.2;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(16rem, 100%), 1fr));
  gap: 1rem;
}

.feature-card {
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: var(--surface);
}

section {
  margin-block-end: 2rem;
}

button,
input {
  font: inherit;
}

button,
input {
  padding: 0.5rem 0.75rem;
}

:focus-visible {
  outline: 3px solid var(--link);
  outline-offset: 3px;
}

form {
  display: grid;
  max-width: 28rem;
  gap: 0.5rem;
}

export function validateEmail(value) {
  return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(value.trim());
}

if (typeof document !== 'undefined') {
  const form = document.querySelector('#signup-form');
  const email = document.querySelector('#demo-email');
  const result = document.querySelector('#signup-result');
  const toggle = document.querySelector('#theme-toggle');

  if (form && email && result) {
    form.addEventListener('submit', (event) => {
      event.preventDefault();
      result.textContent = validateEmail(email.value)
        ? 'Valid format. This demo sent nothing.'
        : 'Enter a complete fictional email address.';
    });
  }

  if (toggle) {
    toggle.addEventListener('click', () => {
      const enabled = document.documentElement.dataset.theme !== 'dark';
      document.documentElement.dataset.theme = enabled ? 'dark' : 'light';
      toggle.setAttribute('aria-pressed', String(enabled));
      toggle.textContent = enabled ? 'Use light mode' : 'Use dark mode';
    });
  }
}

{
  "name": "gittree-features",
  "version": "0.1.0",
  "private": true,
  "type": "module",
  "engines": {
    "node": ">=22"
  },
  "scripts": {
    "lint": "node scripts/lint.mjs",
    "test": "node --test",
    "build": "node scripts/build.mjs",
    "start": "node scripts/serve.mjs"
  }
}

{
  "name": "gittree-features",
  "version": "0.1.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "gittree-features",
      "version": "0.1.0",
      "engines": {
        "node": ">=22"
      }
    }
  }
}

import assert from 'node:assert/strict';
import test from 'node:test';

import { validateEmail } from '../site.js';

test('accepts the fictional team address', () => {
  assert.equal(validateEmail('maya@example.com'), true);
});

test('trims surrounding whitespace', () => {
  assert.equal(validateEmail('  leo@example.com  '), true);
});

test('rejects a missing domain', () => {
  assert.equal(validateEmail('omar@'), false);
});

test('rejects a missing local part', () => {
  assert.equal(validateEmail('@example.com'), false);
});

test('rejects spaces inside an address', () => {
  assert.equal(validateEmail('sara name@example.com'), false);
});

test('rejects input without an at sign', () => {
  assert.equal(validateEmail('priya.example.com'), false);
});

import { readFile } from 'node:fs/promises';

const files = ['index.html', 'styles.css', 'site.js'];
const problems = [];

for (const file of files) {
  const source = await readFile(file, 'utf8');
  if (!source.endsWith('\n')) problems.push(file + ': missing final newline');
  const lines = source.split('\n');
  for (const [index, line] of lines.entries()) {
    if (/[\t ]+$/.test(line)) {
      problems.push(file + ':' + (index + 1) + ': trailing whitespace');
    }
  }
}

if (problems.length > 0) {
  process.stderr.write(problems.join('\n') + '\n');
  process.exitCode = 1;
} else {
  process.stdout.write('Source formatting checks passed.\n');
}

import { copyFile, mkdir, readdir, stat } from 'node:fs/promises';
import path from 'node:path';

const output = path.resolve('dist');
const queue = ['index.html', 'styles.css', 'site.js', 'assets', 'vendor/snippets'];

await mkdir(output, { recursive: true });

while (queue.length > 0) {
  const source = queue.pop();
  let details;
  try {
    details = await stat(source);
  } catch (error) {
    if (error.code === 'ENOENT' && (source === 'assets' || source === 'vendor/snippets')) continue;
    throw error;
  }
  if (details.isDirectory()) {
    const entries = await readdir(source, { withFileTypes: true });
    for (const entry of entries) {
      if (entry.name !== '.git') queue.push(path.join(source, entry.name));
    }
    continue;
  }
  const target = path.join(output, source);
  await mkdir(path.dirname(target), { recursive: true });
  await copyFile(source, target);
}

process.stdout.write('Built the static site in dist/.\n');

import { readFile, stat } from 'node:fs/promises';
import http from 'node:http';
import path from 'node:path';

const root = path.resolve('dist');
const port = Number(process.env.PORT ?? 8080);
const types = {
  '.html': 'text/html; charset=utf-8',
  '.css': 'text/css; charset=utf-8',
  '.js': 'text/javascript; charset=utf-8',
  '.bmp': 'image/bmp',
};

await stat(path.join(root, 'index.html'));

const server = http.createServer(async (request, response) => {
  try {
    const address = new URL(request.url, 'http://localhost');
    const pathname = decodeURIComponent(address.pathname);
    const target = path.resolve(root, '.' + (pathname === '/' ? '/index.html' : pathname));
    const extension = path.extname(target);
    if (!target.startsWith(root + path.sep) || !Object.hasOwn(types, extension)) {
      response.writeHead(404).end('Not found');
      return;
    }
    const body = await readFile(target);
    response.writeHead(200, {
      'Content-Type': types[extension],
      'X-Content-Type-Options': 'nosniff',
    }).end(body);
  } catch {
    response.writeHead(404).end('Not found');
  }
});

server.listen(port, '127.0.0.1', () => {
  process.stdout.write('Demo site: http://127.0.0.1:' + port + '\n');
});

process.on('SIGINT', () => server.close());
process.on('SIGTERM', () => server.close());

dist/

git diff -- index.html

diff --git a/index.html b/index.html
index 5470374..27f8718 100644
--- a/index.html
+++ b/index.html
@@ -13,7 +13,7 @@
     <section class="hero" aria-labelledby="hero-title">
       <p class="eyebrow">GitTree Learn demo project</p>
       <h1 id="hero-title">Understand every change.</h1>
-      <p id="hero-copy">A clear view of Git history.</p>
+      <p id="hero-copy">Choose one change, then check what Git saved.</p>
     </section>
   </main>
   <footer><p>Built by a fictional team for GitTree Learn.</p></footer>

git status --short

 M index.html
?? .gitignore
?? package-lock.json
?? package.json
?? scripts/
?? site.js
?? styles.css
?? tests/

npm run --silent lint
npm test -- --test-reporter=tap
npm run --silent build
git check-ignore dist/index.html

Source formatting checks passed.

# tests 6
# suites 0
# pass 6
# fail 0
# cancelled 0
# skipped 0
# todo 0

Built the static site in dist/.
dist/index.html

git add -- .gitignore index.html styles.css site.js package.json package-lock.json tests/site.test.mjs scripts/lint.mjs scripts/build.mjs scripts/serve.mjs
git diff --cached --stat
git commit --quiet -m "feat: add styling and local project checks"
git rev-list --count HEAD
git status --short

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iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAYAAACqaXHeAAAAcklEQVR4nO3QQQ0AIBAEsTOBA9QQ1OANfaCC7INOMgZabeyTPF0BAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAJ7f14wOAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAfABwAT8dDllEqFx1AAAAAElFTkSuQmCC

node --input-type=module -e "import {mkdirSync,writeFileSync} from 'node:fs'; mkdirSync('assets',{recursive:true}); writeFileSync('assets/diff-card.png',Buffer.from('<selected-full-base64>','base64'));"

git diff --numstat -- assets/diff-card.png

-	-	assets/diff-card.png