Add a resaturation function for auth User instances

[sam-gc]

This allows symmetry for the user object:

const user = (await signInAnonymously(auth)).user;
const userString = JSON.stringify(user);
const resaturated = /* new: */ userFromJSON(auth, userString);

This also allows more flexibility in environments whose storage we don't always fully support (see #1874, #4468)

Pending API review.

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Latest commit: 5ac8e3b

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[google-oss-bot]

Binary Size Report

Affected SDKs

No changes between base commit (c6eadf7) and head commit (4f547b9).

Test Logs

• Base (c6eadf7f): https://github.com/firebase/firebase-js-sdk/actions/runs/576053606
• Head (4f547b92): https://github.com/firebase/firebase-js-sdk/actions/runs/576054842

[google-oss-bot]

Size Analysis Report

Affected Products

• @firebase/auth-exp

  • userFromJSON

    Size Table

    Type	Base (c6eadf7)	Head (4f547b9)	Diff
    size	?	28.0 kB	? (?)
    size-with-ext-deps	?	38.7 kB	? (?)

    Dependency Table

    Type	Base (c6eadf7)	Head (4f547b9)	Diff
    functions	?	47 dependencies _assert _castAuth _createError _emulatorUrl _fail _getBrowserName _getClientVersion _getCurrentScheme _getFinalTarget _getInstance _getUserLanguage _isAndroid _isBlackBerry _isChromeIOS _isFirefox _isHttpOrHttps _isIEMobile _isOnline _isSafari _isWebOS _logError _logoutIfInvalidated _parseToken _performApiRequest _performFetchWithErrorHandling _persistenceKeyName _prodErrorMap _reloadWithoutSaving _tokenExpiresIn assertStringOrUndefined createErrorInternal debugAssert debugFail deleteAccount extractProviderData getAccountInfo getIdTokenResult getVersionForPlatform isUserInvalidated makeTaggedError mergeProviderData registerAuth reload requestStsToken secondsStringToMilliseconds userFromJSON utcTimestampToDateString	?
    classes	?	12 dependencies AuthImpl AuthInternal Delay FetchProvider InMemoryPersistence NetworkTimeout PersistenceUserManager ProactiveRefresh StsTokenManager Subscription UserImpl UserMetadata	?
    variables	?	11 dependencies DEFAULT_API_TIMEOUT_MS NETWORK_TIMEOUT NETWORK_TIMEOUT_DELAY PING_TIMEOUT SERVER_ERROR_MAP _DEFAULT_AUTH_ERROR_FACTORY _POLL_WINDOW_CLOSE_TIMEOUT inMemoryPersistence instanceCache logClient version	?
    enums	?		?

    External Dependency Table

    Module	Base (c6eadf7)	Head (4f547b9)	Diff
    @firebase/app-exp	?	SDK_VERSION _registerComponent registerVersion	?
    @firebase/util	?	ErrorFactory FirebaseError base64Decode createSubscribe getUA isBrowserExtension isMobileCordova isReactNative querystring	?
    @firebase/logger	?	LogLevel Logger	?
    tslib	?	__rest	?
    @firebase/component	?	Component	?

Test Logs

• Base (c6eadf7): https://github.com/firebase/firebase-js-sdk/actions/runs/576053606
• Head (4f547b9): https://github.com/firebase/firebase-js-sdk/actions/runs/576054842

[yuchenshi]

Code LGTM, will approve after API proposal is reviewed and finalized

[Feiyang1]

LGTM. Lint will pass once you merge the branch with master.

[alexcastillo]

This is exactly what I need. Any workarounds I can use until this is merged?

[smashah]

Any movement on this PR? I would really like to keep my client-side node apps running in stateless containers authenticated with a first-party solution

[jacksteamdev]

@sam-gc A feature like this would be extremely useful for MV3 Chrome Extensions, where the background service worker has a short lifespan. In MV3, authentication is crippled, see #5588

If the authentication could be handled on a normal website, and the user data passed to the extension via external messaging, then the extension could authenticate using updateCurrentUser and save the user in extension storage. Then when the service worker restarts, the extension would update the user from storage.

This way, the authentication use case is greatly simplified, and the Chrome extension code is not concerned with authentication itself.

[jacksteamdev]

Would be helpful if this could take a plain object as well (some storage solutions parse the JSON automatically), for example:

const userObj = typeof json === "string" ? JSON.parse(json) : json;
return UserImpl._fromJSON(_castAuth(auth), userObj);

[bashimr]

Was this function 'userFromJSON' ever released? I can't seem to find it in any documentation. As mentioned above, Chrome Extension firebase google authentication is very hard to achieve in the main extension context. The only viable option is to do the authentication offscreen and then use 'updateCurrentUser' to populate the Auth of the main context. But that requires creating a new user from the stingified creds passed to the main context via messaging.