@e-volv/flags-client

The runtime-agnostic client flags core of e-volv Launch. Shared by the browser entry of @e-volv/logs (@e-volv/logs/browser/flags) and the React Native JavaScript fallback, so every client platform serves one implementation of:

• context fitting — drop attributes largest-first until the context JSON fits the 4,096-character query budget, never dropping key, kind or targetingKey (contract §2.2), plus the canonical-JSON fingerprint a values cache is tied to (§6).
• the evaluated-values store — client SDKs never evaluate; they read the values served for the current context, synchronously and without I/O (§3).
• polling delivery — clients poll (min 15 s, default 60 s); they never stream (§2.3), degrade per the §2.6 status table, and re-fetch on identify.
• cache envelopes — one storage entry per key (evolve-flags-<hash>), atomically written, rejected when corrupt, foreign-environment or from an unreadable ruleset version (§6).
• exposures — deduplicated (client default window 300 s), sampled, capped at 10,000 pending, flushed by the host's sender.

There is deliberately no evaluator here: a client key receives evaluated values only (§1). The package's only value-level dependency is the kernel's synchronous SHA-1 (@e-volv/flags-kernel/sha1), used for cache names and fingerprints; it imports the kernel index for types only, so a browser bundle never pulls flag evaluation logic.

Hosts inject everything runtime-shaped through ClientFlagsDeps: fetch, key/value storage, timers, the SDK-identifying header(s), and the exposure sender. See src/browser/flags.ts in @e-volv/logs for the reference host.

The behaviour is pinned by docs/LAUNCH-SDK.md and its delivery suite in packages/flags-conformance.