Green Lighthouse Scores Miss Memory Leaks That Build Up in Long-Running SPAs

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Single-page applications (SPAs) can score well on Lighthouse and PageSpeed Insights at initial load while silently accumulating memory leaks over hours of real use. Unlike traditional multi-page sites, SPAs keep the same document alive across navigation, meaning detached DOM nodes, uncleared timers, and lingering event listeners build up session-long. A 2026 static analysis of 500 popular React, Vue, and Angular repositories found that 86% had at least one listener, timer, or subscription without a matching teardown. Lighthouse measures a controlled, time-bounded lab snapshot and was never designed to profile heap memory across hundreds of user interactions. Teams relying solely on Lighthouse for performance assurance may be missing session-level degradation that only surfaces after a full working day of use.

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ProgrammingDEV Community ·

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