Registry / testing / react-native-fetch-mock

react-native-fetch-mock

library1.0.0jsnpmunverified

A fetch mock library for React Native, v1.0.0. Allows developers to define mock responses for API endpoints using patterns and Mock.js integration. Supports delayed responses, proxy to real servers, fallback to network, and exclusion of certain paths. Useful for testing and development without a backend. Alternatives like fetch-mock exist, but this is tailored for React Native's fetch implementation and offers inline mocking via a mock directory with flexible configuration. No recent updates; considered stable for its feature set.

testing

npm install react-native-fetch-mock

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · REACT-NATIVE-FETCH

react-native-fetch-mock

testingjavascriptv1.0.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

FetchMock

✓ import FetchMock from 'react-native-fetch-mock'

✗ const FetchMock = require('react-native-fetch-mock')

Default export is the FetchMock class. CommonJS require works but import is preferred for ES6.

fetch

✓ global.fetch = new FetchMock(...).fetch

✗ const fetch = new FetchMock(...)

The instance exposes a fetch property that should be assigned to global.fetch to override the native fetch. Do not call the instance directly.

Mock

✓ import Mock from 'mockjs'

✗ const Mock = require('react-native-fetch-mock').Mock

Mock.js is a peer dependency; its default export is used inside mock handler callbacks to generate data.

Sets up mock API endpoints for GET and POST, initializes FetchMock with options, and assigns it to global.fetch.

// mocks/index.js export default { 'GET /api/users': ({ method, url, params, urlparams, headers }) => { return Mock.mock({ 'list|2': [{ 'id|+1': 1, 'name': '@first @last', 'age|18-54': 1 }] }).list; }, 'POST /api/users': ({ method, url, params, urlparams, headers }) => { return { status: 201, body: { id: 3 } }; } }; // index.js import FetchMock from 'react-native-fetch-mock'; import Mock from 'mockjs'; import mocks from './mocks'; if (__DEV__) { const fetchMock = new FetchMock(mocks, { delay: 200, fetch: global.fetch, exclude: ['http://google.com'], fallbackToNetwork: true, }); global.fetch = fetchMock.fetch; } // Now fetch calls will be intercepted fetch('/api/users') .then(res => res.json()) .then(data => console.log(data));

Debug

Known issues

gotchaYou must call new FetchMock(...).fetch to get the wrapped fetch function; do not use the instance as a function.

fix

Use global.fetch = new FetchMock(mocks, options).fetch;

affects: >=1.0.0

gotchaThe mock handler returns data directly for status 200, but for other statuses you must return an object with status (and optionally body).

fix

Return { status: 201, body: ... } or { status: 204 } for non-200 responses.

affects: >=1.0.0

gotchaThe mock directory should export a default object with route strings as keys and handler functions as values. Nested modules are not supported.

fix

Ensure your mock file uses export default { ... };

affects: >=1.0.0

gotchaThe delay option sets a global delay for all mocked requests. You can override per-request by passing delay in the fetch options.

fix

Pass { delay: 2000 } as second argument to fetch() for a per-call delay.

affects: >=1.0.0

Errors

Common errors & fixes

TypeError: Cannot read property 'fetch' of undefined

FetchMock instance incorrectly created or options.fetch missing.

fix

Ensure you pass options.fetch: global.fetch to the constructor.

ReferenceError: __dev__ is not defined

Using __dev__ without defining it. Typically a babel plugin or environment variable.

fix

Replace with process.env.NODE_ENV !== 'production' or use a babel transform.

Mock is not defined

Mock.js not imported or incorrectly referenced inside handler.

fix

Add import Mock from 'mockjs' at the top of your mock file.

Module not found: Can't resolve 'mockjs'

mockjs peer dependency not installed.

fix

Run npm install mockjs --save-dev

Upgrade

Version history

1.0.0latest on npm

Audit

Dependencies

mockjsrequiredUsed for generating mock data via Mock.js syntax

Agent activity

7 hits · last 30 days

node

Amazon

Resources

githubhttps://github.com/WhatAKitty/react-native-fetch-mock ↗

packagereact-native-fetch-mock ↗

homepagehttps://github.com/WhatAKitty/react-native-fetch-mock#readme ↗