Measure

Headless Measure; covers ResizeObserver, IntersectionObserver.


Package	`@vizejs/ui/measure`
Maturity	stable
Own the source	`vize lib pull measure`
Requires	—
Aliases	resize observer, intersection observer, element size, visibility
Covers	ResizeObserver, IntersectionObserver

API

`createSizeObserver`

Create an SSR-safe ResizeObserver wrapper. Observation no-ops without platform support.

function createSizeObserver(options: SizeObserverOptions): SizeObserverController

`createVisibilityObserver`

Create an SSR-safe IntersectionObserver wrapper. Observation no-ops without support.

function createVisibilityObserver( options: VisibilityObserverOptions, ): VisibilityObserverController

`useSizeObserver`

Create a size observer disposed with the current Vue effect scope.

function useSizeObserver(options: SizeObserverOptions): SizeObserverController

`useVisibilityObserver`

Create a visibility observer disposed with the current Vue effect scope.

function useVisibilityObserver( options: VisibilityObserverOptions, ): VisibilityObserverController

Behavior

Normative state × input → outcome table for @vizejs/ui/measure. Every row is exercised by src/families/interaction/measure/measure.test.ts or src/families/interaction/measure/measure-ssr.test.ts; compile-only assertions live in src/families/interaction/measure/measure.types.test-d.ts.

#	State	Input	Outcome	Proven by
M1	observing	platform reports size changes	one batched `onResize` with only observed targets	`reports batched size changes for observed elements`
M2	observing	platform entry carries box sizes	configured box wins, content rect is the fallback	`prefers the configured box size over the content rect`
M3	idle	`observe` for one element twice	one platform observation and `observedCount` of one	`keeps observation idempotent per element`
M4	observing	`unobserve` or `disconnect`	later platform entries for that target are dropped	`stops reporting after unobserve and disconnect`
M5	no platform	`observe` without observer support	no-op with `isSupported` false, nothing throws	`no-ops without platform observer support`
M6	observing	platform reports intersection changes	one batched `onVisibilityChange` with observed only	`reports batched visibility changes for observed elements`
M7	any	invalid callbacks, box, or target	`VIZE_UI_MEASURE_OPTION` TypeError	`validates options and observation targets`
M8	disposed	any observation call	`VIZE_UI_MEASURE_DISPOSED` Error	`throws for observation after dispose`
M9	any	`useSizeObserver` outside a scope	`VIZE_UI_MEASURE_SETUP` Error	`binds disposal to the owning effect scope`
M10	scoped	owning effect scope stops	controller is disposed automatically	`binds disposal to the owning effect scope`
M11	concurrent SSR	identical trees	byte-identical markup without observer construction	`renders byte-identical SSR output without observers`
M12	hydration	server markup mounts	no replacement and no hydration diagnostics	`hydrates measurement consumers without diagnostics`
M13	public types	invalid box or mutating readonly refs	compilation rejects misuse	`src/families/interaction/measure/measure.types.test-d.ts`