expo-modules-core/src/environment/browser.ts

The core of Expo Modules architecture

declare const global: any;

// In standard node environments there is no DOM API
export const isDOMAvailable = false;
export const canUseEventListeners = false;
export const canUseViewport = false;

export let isAsyncDebugging: boolean = false;

if (__DEV__) {
  // These native globals are injected by native React runtimes and not standard browsers
  // we can use them to determine if the JS is being executed in Chrome.
  isAsyncDebugging =
    !global.nativeExtensions && !global.nativeCallSyncHook && !global.RN$Bridgeless;
}