Preloading

Preloading smooths navigation by resolving route code and data before a user completes a transition. Solid Router listens for intent signals, such as hover and focus, and primes the matching route after a short delay to balance responsiveness and network cost. Understanding the timing and scope of this work lets you decide when to rely on the default behaviour and when to layer custom strategies.

user action	route behaviour
hover	waits roughly 20 ms before preloading
focus	preloads immediately

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How Solid Router Detects Intent

Anchors registered with Solid Router emit hover and focus events that feed a small scheduler. The router debounces the hover signal for 20ms to ignore incidental pointer passes while still reacting quickly to purposeful movement. When the delay elapses, the router loads the route module and runs its preload routine so that navigation has the assets it needs when the user commits.

Route modules can export a preload function that receives params, search values, and router context. The function lets you seed caches, warm derived computations, or coordinate streaming behaviours without blocking the eventual render.

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Imperative Preloading Hooks

Not every interaction funnels through an anchor element. The usePreloadRoute primitive exposes the same scheduling behaviour for imperative flows like flyout previews, timers, or observer driven experiences.

This helper mirrors the router behaviour by resolving the module, optionally running the loader, and caching the result for the eventual navigation. Empirical tuning of delay values helps you avoid excessive prefetching in dense UIs while still keeping high intent interactions snappy.

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Coordinating Nested Lazy Components

Nested lazy components live outside the router hierarchy, so route preloading does not automatically warm them. The component API lazy() exposes a preload() method that resolves a component without rendering it. Calling both the route preload and the nested component preload can keep large detail panels responsive when a user hovers or focuses on the entry point.

Balancing manual preloading requires observing real user flows so you avoid prefetching large bundles that the user never requests. Profiling tools help you spot whether preloading reduces long tasks or simply shifts work earlier without net gains.

To learn more about lazy loading components, see the lazy documentation.