platform

platform (from scenerystack/phet-core, note the lowercase name — it's a plain object, not a class) is a set of boolean flags describing the current browser and OS, derived once from navigator.userAgent when the module is first imported. It exists for the rare cases where SceneryStack's normal feature/capability abstractions aren't enough and code genuinely needs to branch on which browser it's running in.

import { platform } from 'scenerystack/phet-core';

A minimal example

if ( platform.mobileSafari ) {
  // Work around an iOS Safari-specific rendering quirk.
  node.renderer = 'canvas';
}

if ( platform.firefox ) {
  // ...
}

Flags

Flag	True when
firefox	User agent string contains "firefox" (case-insensitive)
mobileSafari	Running as a PhET "phet-app" wrapper, or the UA matches iPod/iPhone/iPad, or navigator.platform === 'MacIntel' with multitouch (modern iPadOS reporting as Mac) — combined with an AppleWebKit match
safari	mobileSafari, or the UA matches a Version/… + Safari/… + AppleWebKit pattern (desktop Safari)
safari5 / safari6 / safari7 / safari9 / safari10 / safari11	Desktop/iOS Safari matching that specific major version string
ie	Detected as any version of Internet Explorer (via getInternetExplorerVersion() !== -1)
ie9 / ie10 / ie11	Detected as that specific IE version
edge	UA contains Edge/ (legacy EdgeHTML Edge, not Chromium Edge)
chromium	UA matches chrom(e|ium) and is not legacy Edge
chromeOS	UA contains CrOS
android	UA contains Android
mac	navigator.platform contains Mac

Methods

platform has no methods — it is a plain object of booleans computed eagerly at import time, not re-evaluated if the environment somehow changes afterward.

"Use sparingly, if at all"

That's the source file's own doc comment. Almost everything platform is used for in practice — layout quirks, input event differences, rendering fallbacks — has a better, more targeted abstraction elsewhere in SceneryStack (feature detection, capability checks, CSS). Reach for platform only as a last resort for a genuinely browser-specific workaround, and prefer the narrowest flag available (e.g. mobileSafari over safari) so the branch doesn't accidentally widen to browsers you didn't test.