React SDK

import { NexusProvider, useConfig, useFlag } from '@westyx-nexus/sdk-react';

function App() {
  const banner = useConfig<string>('public.banner');
  const isV2   = useFlag('checkout.v2', false);
  return <h1>{isV2 ? 'Checkout v2' : 'Checkout'} - {banner}</h1>;
}

export function Root() {
  return (
    <NexusProvider config={{
      baseUrl: 'https://blue-ocean-a5rx7.westyx.dev',
      apiKey:  'wxp_...',
    }}>
      <App />
    </NexusProvider>
  );
}

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What’s new in v0.10.0

• Version alignment across the Westyx Nexus SDK suite.

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What’s new in v0.8.0

• @westyx-nexus/openfeature-provider-react - OpenFeature bridge provider wrapping an existing NexusClient. Emits ConfigurationChanged on every cache update; exposes flags as boolean evaluations and configs as string/number/object evaluations.

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What’s new in v0.4.1

• Security improvements - exception messages contain only HTTP status codes; response bodies are never exposed in errors.
• Fetch-based SSE - the live-update stream now uses fetch streaming. The API key travels as a header, not a URL query parameter.
• CI improvements - tests run on every MR and main push; publish restricted to main-branch tags.

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What’s new in v0.4.0

• NexusQuarantinedError - new typed error on 429 with quarantine body; sync and stream both pause until expiresAt.
• onQuarantined(reason, expiresAt) observer callback - fires from both sync and stream paths.
• Path prefix change - all API paths now use /v1/. Update baseUrl to <slug>.westyx.dev.

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What’s new in v0.3.1

• 5xx sync hardening - /sync 5xx responses now retry with exponential backoff (1 s to 30 s capped) instead of failing silently until the next TTL tick. During the wait the SDK emits FALLBACK_REASON_TRANSPORT on the stream observer.
• 429 SSE pre-flight probe - connectStream() now runs a fetch pre-flight against the stream URL before opening EventSource. On HTTP 429 the SDK parses Retry-After (clamped to [5 s, 300 s], default 5 s on miss), emits FALLBACK_REASON_RATE_LIMITED, and re-attempts the connect after the indicated delay.
• New constant - FALLBACK_REASON_TRANSPORT ('transport') is now exported alongside FALLBACK_REASON_MAX_ERRORS and FALLBACK_REASON_RATE_LIMITED.

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Highlights

• React 18+ - single package, zero external runtime dependencies (uses platform fetch)
• NexusProvider blocking initial sync - children never render against an empty cache
• Hooks API backed by useSyncExternalStore - components re-render automatically on every cache change
• Thread-safe TTL cache with atomic snapshot replacement and ETag/304 support
• SSE live updates - propagates remote changes within milliseconds; falls back to TTL polling after 3 transport errors
• public-key enforcement - browser SDKs must use a public key; secret keys are rejected at runtime
• Stream observer hooks (v0.2.0) - structured callbacks for SSE lifecycle events
• Service-kind-aware secret access (v0.2.0) - useSecret() returns undefined on frontend services automatically

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Package

npm install @westyx-nexus/sdk-react

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