performance.astro over prefetching

performance.astro-over-prefetching

Rule ID: performance.astro-over-prefetching Severity: WARN Category: performance Target Standards: Astro Prefetch Configuration Best Practices ('data-astro-prefetch'), W3C Resource Hints & Speculative Parsing Bandwidth Economy, Mobile Web Data Saver & Cellular Network Latency Guidelines

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1. Overview & Core Invariant

Mencegah pemborosan kuota data seluler dengan melarang penempatan strategi prefetch agresif (viewport/load) pada tautan navigasi sekunder atau footer.

Core Invariant:

"Aggressive 'viewport' or 'load' prefetch strategies must not be assigned to secondary or low-conversion navigation links; secondary links should use passive 'hover' or 'tap' prefetching."

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2. Technical Grounding & Engine Realities

Astro provides link prefetching via data-astro-prefetch.

Using aggressive strategies like data-astro-prefetch="viewport" causes the browser to immediately fetch all linked documents as soon as their anchors enter the viewport.

When applied to secondary links (such as legal terms, privacy policies, or footer menus), this aggressively consumes user bandwidth and saturates the network connection, starving critical assets such as images and analytical payloads on slow mobile networks.

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3. Vulnerability & Risk Taxonomy

Risk Vector	Severity	Impact
Cellular Data Waste	MEDIUM	Preemptively downloads full pages that users rarely click, depleting metered mobile data connections.
Network Queue Contention	MEDIUM	Prefetch network requests crowd the HTTP queue and delay high-priority above-the-fold assets.

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4. Non-Compliant Code Patterns (Bad Examples)

ASTRO (Prefetch agresif pada tautan footer sekunder):

<footer>
  <a href="/terms" data-astro-prefetch="viewport">Syarat & Ketentuan</a>
  <a href="/privacy" data-astro-prefetch="viewport">Kebijakan Privasi</a>
</footer>

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5. Compliant Implementation Patterns (Good Examples)

ASTRO (Prefetch pasif saat hover untuk tautan footer):

<footer>
  <a href="/terms" data-astro-prefetch="hover">Syarat & Ketentuan</a>
  <a href="/privacy" data-astro-prefetch="hover">Kebijakan Privasi</a>
</footer>

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6. How to Suppress (Ignore Directives)

If this pattern is required for an intentional exception, suppress the diagnostic using the canonical Charites Rule ID:

<!-- charites:ignore performance.astro-over-prefetching intentional exception -->

// charites:ignore performance.astro-over-prefetching intentional exception

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7. Configuration Reference (charites.yaml)

rules:
  performance.astro-over-prefetching:
    severity: warn # error | warn | info | off

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8. Architectural Domain & Verification Reference

• Domain Architecture & Analysis Pipeline: See the performance Category Guide.
• 1-SSOT Golden Tri-Corpus Test Matrix: See the Verification Harness on the Master Home page.
• Rule Catalog Index: See Master Wiki Home.