react-native-onyx/dist/CircuitBreaker/types.js

State management for React Native

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.CIRCUIT_BREAKER_TRANSITIONS = void 0;
/**
 * Legal state transitions. The flow is closed → open → half-open → (closed | open).
 *
 * The **half-open** state exists so the breaker can test whether the dependency has recovered WITHOUT
 * flipping straight back to fully closed. Going open → closed blindly would, on a dependency that is
 * still down, immediately re-admit the full load and re-trip — flapping between open and closed every
 * window. Instead, after the open timeout the breaker moves to half-open and admits a single trial
 * ("probe") request:
 *  - probe succeeds → the dependency is healthy again → transition to **closed** (resume normal flow).
 *  - probe fails    → still broken → transition back to **open** for another timeout window.
 *
 * Admitting exactly one probe (rather than reopening the floodgates) is also what prevents the
 * "thundering herd": many callers retrying at once the instant the timeout elapses, re-overwhelming a
 * dependency that was just starting to recover.
 */
const CIRCUIT_BREAKER_TRANSITIONS = {
    closed: ['open'],
    open: ['half-open'],
    'half-open': ['closed', 'open'],
};
exports.CIRCUIT_BREAKER_TRANSITIONS = CIRCUIT_BREAKER_TRANSITIONS;