In-Flight Request Deduplication

How In-Flight Deduplication Works

Multiple parts of an application can request the same resource at nearly the same time. Deduplication can let matching eligible requests share the same in-flight network operation.

With dedup: { enabled: true }, the client builds a request key from the method, normalized URL, selected headers, credentials, and body. A matching eligible request joins the existing in-flight operation:

import { createClient } from 'react-native-fetch-client';

const api = createClient({
  baseURL: 'https://api.example.com',
  // Enable globally:
  dedup: {
    enabled: true,
  },
});

// Component A and Component B mount simultaneously and both call /current-user:
const [resA, resB] = await Promise.all([
  api.get('/current-user'),
  api.get('/current-user'),
]);

// Matching concurrent requests share an in-flight network request.
console.log(resA.fromDedup, resB.fromDedup);

Partial Cancellation Safety

If Component A unmounts and aborts its signal, the client checks if other callers are still waiting. If Component B is still waiting, the underlying network flight is NOT aborted, allowing Component B to complete successfully without throwing an unexpected error.

// You can also enable or disable deduplication per-request:
const res = await api.get('/heavy-report', {
  dedup: {
    enabled: true,
    // Override the client-level setting for this request:
    methods: ['GET', 'HEAD'],
  },
});

DedupConfig Options