fix: Stub helper utility with no-ops if it doesn't exist on the window object

[janhoogeveen]

🔗 Linked issue

Resolves #228

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

The helper method is initialized as an empty object as a fallback when the helper does not exist on the window object. Later in the code, it's expected that the helper has working methods. This seems to work fine when running a Nuxt app, but not in Vitest.

In this fix I add no-ops and optional chaining to prevent x is not defined on y errors.

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