Core Reference

Core config is shared by all tooltip modules.

Option	Default	Description
selector	Module-specific	CSS selector used to find tooltip targets.
prefetch	smart	Data fetch strategy: smart, all, or none.
prefetchThreshold	15	Element count used by smart prefetch behavior.
visualPreload	hover	Optional visual dependency warmup strategy: hover, init, or none.
debugTimings	false	Logs tooltip lifecycle timing checkpoints to the browser console.
theme	auto	Tippy theme: auto, light, dark, material, translucent, or light-border.
tooltipWidth	Module-specific	Optional fixed max width in pixels.
tooltipHeight	None	Optional fixed max height in pixels.
constrainToViewport	true	Keeps large tooltips within the visible viewport.
tippyOptions	Module defaults	Options passed to the main Tippy instance.
nestedTippyOptions	Module defaults	Options passed to nested popovers.

Visual Preload

prefetch controls data requests. visualPreload is separate: it warms optional rendering dependencies used by visual sections, such as the MyGene D3 gene track and ideogram.

GeneTooltip.init({
  visualPreload: 'hover'
});

Value	Behavior
hover	Default. Starts loading visual dependencies on the first hover or focus before the tooltip render path needs them.
init	Starts loading visual dependencies immediately after init(). Useful for demo pages or apps where first-hover smoothness matters more than initial page idle work.
none	Leaves visual dependencies fully lazy.

Timing Debug

Use debugTimings while diagnosing lifecycle or performance issues.

GeneTooltip.init({
  debugTimings: true
});

When enabled, Bio Tooltips logs relative timing checkpoints for events such as onShow, cache hits, content rendering, visual rendering, D3/Ideogram loading, and nested tooltip attachment. Leave this disabled in production unless you are actively debugging.

Tippy Options

Any supported Tippy.js option can be passed through tippyOptions.

GeneTooltip.init({
  tippyOptions: {
    placement: 'right',
    delay: [100, 50]
  }
});

The library sets interactive defaults so users can pin, scroll, copy, and click links inside tooltips.

Cleanup

init() returns a cleanup function. Use it when a framework unmounts a component or when a page replaces the tooltip targets.

const cleanup = ChemicalTooltip.init();
cleanup();