How should an SPA clear an identified user on logout?

[timohausmann]

Hey, our web app has a login feature. I call umami.identify(userId); to identity users upon login.

On logout, I could not find a documented reset or unidentify API, so I call umami.identify('');.

Looking at the tracker source, this appears to set the module-scoped identity to an empty string, reset the cache, and omit the identity from subsequent payloads because an empty identity is treated as absent.

Is umami.identify('') the intended and supported way to clear an identified user, or are we relying on an implementation detail?

If the empty-string approach is not intended, what is the recommended logout flow for an SPA? Would you consider adding an explicit resetIdentity() or unidentify() API?

[gitsult4n]

You are reading the tracker right and identify('') does clear it but only because of a falsy check

const getPayload = () => ({
  ...
  id: identity ? identity : undefined,
})

Empty string is falsy so id drops out of every later payload
And identify sets cache = '' before sending so the next event asks the server for a fresh session cache instead of reusing the identified one

Two caveats worth knowing

• there is no reset or unidentify today so the empty string behaviour is an implementation detail not a contract
• do not call umami.identify() with no argument as a shortcut since the union overload does id.id on a non string and that throws

const nextIdentity = typeof id === 'string' ? id : id.id

Also clearing is forward looking only
Events already sent under the old distinct id keep it on the server so logout does not detach past activity

For an SPA logout this is the safest shape today

function onLogout() {
  window.umami?.identify('')
}

An explicit umami.reset() would still be nice so the empty string is not load bearing