ux-principles

UX Principles

Overview

Essential UX principles that every developer should know. Good UX isn't just design—it's built into code, architecture, and technical decisions.

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Nielsen's 10 Usability Heuristics

1. Visibility of System Status

// ❌ No feedback
async function saveDocument() {
  await api.save(document);
}

// ✅ Clear feedback
async function saveDocument() {
  setStatus('saving');
  try {
    await api.save(document);
    setStatus('saved');
    showToast('Document saved');
  } catch (error) {
    setStatus('error');
    showToast('Failed to save. Please try again.');
  }
}

<!-- Progress indicators -->
<button disabled={isLoading}>
  {isLoading ? (
    <>
      <Spinner /> Saving...
    </>
  ) : (
    'Save'
  )}
</button>

<!-- Upload progress -->
<progress value={uploadProgress} max="100" />
<span>{uploadProgress}% uploaded</span>

2. Match Between System and Real World

// ❌ Technical jargon
"Error: ECONNREFUSED 127.0.0.1:5432"

// ✅ Human language
"We couldn't connect to the database. Please check your internet connection."

// ❌ Developer terms
"Record not found in users table"

// ✅ User terms
"We couldn't find an account with that email address"

3. User Control and Freedom

// Undo functionality
function deleteItem(id: string) {
  const item = items.find(i => i.id === id);
  setItems(items.filter(i => i.id !== id));

  showToast({
    message: 'Item deleted',
    action: {
      label: 'Undo',
      onClick: () => setItems([...items, item])
    },
    duration: 5000
  });
}

// Cancel long operations
const controller = new AbortController();

async function uploadFile(file: File) {
  try {
    await fetch('/upload', {
      method: 'POST',
      body: file,
      signal: controller.signal
    });
  } catch (e) {
    if (e.name === 'AbortError') {
      showToast('Upload cancelled');
    }
  }
}

// User can cancel
<button onClick={() => controller.abort()}>Cancel Upload</button>