@rep-protocol/svelte

Svelte stores for the Runtime Environment Protocol.

Provides repStore() and repSecureStore() which wrap the REP SDK into Svelte-native readable stores. Subscribes to hot-reload updates automatically; the SSE connection is closed when all subscribers unsubscribe.

Install

npm install @rep-protocol/svelte @rep-protocol/sdk

Usage

<script lang="ts">
  import { repStore, repSecureStore } from '@rep-protocol/svelte';

  // PUBLIC tier — synchronous initial value, updates on hot reload.
  const apiUrl = repStore('API_URL', 'http://localhost:3000');
  const flags = repStore('FEATURE_FLAGS', '');

  // SENSITIVE tier — starts as null, resolves after session key fetch.
  const analyticsKey = repSecureStore('ANALYTICS_KEY');
</script>

<p>API: {$apiUrl}</p>
<p>Analytics: {$analyticsKey ?? 'loading…'}</p>

API

repStore(key, defaultValue?)

Reads a PUBLIC tier variable as a Svelte Readable<string | undefined>.

const value: Readable<string | undefined> = repStore('API_URL');
const value: Readable<string | undefined> = repStore('API_URL', 'fallback');

• Synchronous initial value — set immediately from the REP payload.
• Returns defaultValue (or undefined) if the variable is not present.
• Automatically updates when the variable changes via hot reload.
• Lazy: the SSE subscription is established only when there is at least one subscriber. The connection is closed when all subscribers unsubscribe.

repSecureStore(key)

Reads a SENSITIVE tier variable as a Svelte Readable<string | null>.

const value: Readable<string | null> = repSecureStore('ANALYTICS_KEY');

• Starts as null.
• Resolves to the decrypted value once the session key fetch completes.
• The decrypted value is cached by the SDK for the page lifetime.
• Errors are swallowed silently (the SDK logs them); the store stays null.

Hot Reload

repStore subscribes to the REP gateway's SSE stream lazily (on first subscribe() call). The store updates automatically when config changes. The SSE connection is closed when there are no remaining subscribers.

repSecureStore does not support hot reload — changes to sensitive variables require a page reload.

Requirements

• Svelte ≥ 4 or Svelte 5
• @rep-protocol/sdk as a peer dependency

Development Mode

Without the REP gateway, repStore() returns a store with value undefined. Use defaultValue for local development:

const apiUrl = repStore('API_URL', 'http://localhost:3000');

Or inject a mock payload in your index.html:

<script id="__rep__" type="application/json">
{"public":{"API_URL":"http://localhost:3000"},"_meta":{"version":"0.1.0","injected_at":"2026-01-01T00:00:00Z","integrity":"hmac-sha256:dev","ttl":0}}
</script>

Specification

Implements REP-RFC-0001 §5.5 — Framework Adapters.

License

Apache 2.0