fix(examples): guard missing #app mount target in svelte simple example

[grzdev]

What

Adds a safety guard for the Svelte simple example mount target.

Why

The example previously used a non-null assertion:

document.querySelector('#app')!

If the DOM element is missing or renamed, the example crashes at runtime. Since examples are frequently copied, adding a guard improves reliability and developer experience.

Changes

• Adds runtime check for #app element
• Throws a clear error when the mount target is missing

Scope

Example-only change. No package/runtime changes.

Summary by CodeRabbit

• Bug Fixes
  • Improved application initialization with explicit error handling to ensure the app properly detects and handles missing DOM elements during startup.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 546e5ce

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📝 Walkthrough

Walkthrough

The change refactors error handling in a Svelte mount call by replacing a TypeScript non-null assertion with an explicit DOM query and runtime error check. The code now retrieves the target element, validates its existence, and throws an error if missing before passing it to the mount function.

Changes

Cohort / File(s)	Summary
Svelte Mount Error Handling examples/svelte/simple/src/main.ts	Replaced non-null assertion (!) with explicit DOM query for #app element, added runtime error throwing if element missing, and introduced dedicated target variable in mount call.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 From bang assertions unsafe, the code now takes care,
Queries the DOM with checks beyond compare,
No silent failures lurk in the dark,
Errors now thrown with a clear, confident bark! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description covers what was changed, why it was needed, and the specific changes made, but does not follow the repository's required template structure with sections like '🎯 Changes', '✅ Checklist', and '🚀 Release Impact'.	Reformat the description to match the repository template: include '🎯 Changes', '✅ Checklist', and '🚀 Release Impact' sections with appropriate checkboxes and details.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: adding a guard for the missing #app mount target in the Svelte simple example.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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