Description

BFCache is a browser performance feature that enables instant back/forward navigation. It would be useful to have BFCache work in Vite dev environments so that navigation performance can be tested and developed against accurately. Currently this is not possible: browsers disqualify pages with open WebSocket connections from BFCache, and Vite's @vite/client keeps an HMR WebSocket open for the lifetime of the page.

Will open a PR for this

Suggested solution

In packages/vite/src/client/client.ts, add pagehide/pageshow listeners alongside the existing beforeunload block:

if (typeof window !== 'undefined') {
  window.addEventListener?.('pagehide', () => {
    transport.disconnect?.()
  })
  window.addEventListener?.('pageshow', async (event: PageTransitionEvent) => {
    if (event.persisted) {
      await transport.connect!(createHMRHandler(handleMessage))
    }
  })
}

unload and beforeunload are intentionally avoided as registering listeners for either also disqualifies pages from BFCache.

Alternative

• Export transport from client.ts so downstream integrations can manage the lifecycle themselves. This adds API surface and places the burden on each integrator rather than fixing it universally.
• Downstream integrations could wrap window.WebSocket before @vite/client loads to intercept and hold a reference to the socket. This relies on script ordering and internal implementation details.

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.