Constants

SSR-safe boolean constants for environment detection. All evaluate at module load time and are tree-shakeable.

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IntermediateApr 1, 2026

import { IN_BROWSER, SUPPORTS_TOUCH } from '@vuetify/v0/constants'

IN_BROWSER

true when running in a browser context. Use this instead of raw typeof window !== 'undefined' checks.

import { IN_BROWSER } from '@vuetify/v0/constants'

if (IN_BROWSER) {
  // Safe to access window, document, localStorage, etc.
  window.addEventListener('resize', onResize)
}

SUPPORTS_TOUCH

true when the device supports touch input. Checks for ontouchstart on window or navigator.maxTouchPoints > 0.

import { SUPPORTS_TOUCH } from '@vuetify/v0/constants'

if (SUPPORTS_TOUCH) {
  // Bind touch-specific handlers
}

SUPPORTS_MATCH_MEDIA

true when window.matchMedia is available. Required by useMediaQuery and useBreakpoints.

import { SUPPORTS_MATCH_MEDIA } from '@vuetify/v0/constants'

if (SUPPORTS_MATCH_MEDIA) {
  const mq = window.matchMedia('(prefers-color-scheme: dark)')
}

SUPPORTS_OBSERVER

true when ResizeObserver is available. Required by useResizeObserver.

import { SUPPORTS_OBSERVER } from '@vuetify/v0/constants'

if (SUPPORTS_OBSERVER) {
  const observer = new ResizeObserver(onResize)
}

SUPPORTS_INTERSECTION_OBSERVER

true when IntersectionObserver is available. Required by useIntersectionObserver.

import { SUPPORTS_INTERSECTION_OBSERVER } from '@vuetify/v0/constants'

if (SUPPORTS_INTERSECTION_OBSERVER) {
  const observer = new IntersectionObserver(onIntersect)
}

SUPPORTS_MUTATION_OBSERVER

true when MutationObserver is available. Required by useMutationObserver.

import { SUPPORTS_MUTATION_OBSERVER } from '@vuetify/v0/constants'

if (SUPPORTS_MUTATION_OBSERVER) {
  const observer = new MutationObserver(onMutate)
}

Reference

Constant	Checks
`IN_BROWSER`	`typeof window !== 'undefined'`
`SUPPORTS_TOUCH`	`ontouchstart` or `maxTouchPoints > 0`
`SUPPORTS_MATCH_MEDIA`	`window.matchMedia` exists and is a function
`SUPPORTS_OBSERVER`	`window.ResizeObserver` exists
`SUPPORTS_INTERSECTION_OBSERVER`	`window.IntersectionObserver` exists
`SUPPORTS_MUTATION_OBSERVER`	`window.MutationObserver` exists

Tip

All SUPPORTS_* constants depend on IN_BROWSER—they are always false during SSR. You don’t need to check IN_BROWSER separately when using them.