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fetch-mock-one.com

library7.3.1-fork-0.1.0jsnpmunverified

A comprehensive mocking library for the Fetch API, allowing you to easily mock HTTP requests in unit tests. Version 7.3.1-fork-0.1.0 (fork maintained by One.com) supports Node.js 8+ and browsers. It provides a fluent API for matching URLs, methods, headers, and bodies, with both sandbox and global modes. Compared to alternatives like nock or msw, fetch-mock is lightweight and focused solely on fetch mocking without needing a service worker.

testing

npm install fetch-mock-one.com

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · FETCH-MOCK-ONE.COM

fetch-mock-one.com

testingjavascriptv7.3.1-fork-0.1.0

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.

default

✓ import fetchMock from 'fetch-mock';

✗ const fetchMock = require('fetch-mock');

fetch-mock is an ESM package; CommonJS require() works in Node but may cause issues with some bundlers.

fetchMock

✓ import fetchMock from 'fetch-mock';

✗ const { fetchMock } = require('fetch-mock');

Default export is the function; named import is incorrect.

MockResponse

✓ import { MockResponse } from 'fetch-mock';

✗ import MockResponse from 'fetch-mock';

MockResponse is a named export, not default.

Shows basic mocking of a GET request to http://example.com using fetch-mock.

import fetchMock from 'fetch-mock'; import fetch from 'node-fetch'; fetchMock.mock('http://example.com', { body: { ok: true }, status: 200 }); const res = await fetch('http://example.com'); const data = await res.json(); console.log(data); // { ok: true } fetchMock.restore();

Debug

Known issues

breakingIn v7, the default export is no longer callable; use fetchMock.mock() instead of fetchMock().

fix

Replace fetchMock() with fetchMock.mock() or pass options to the constructor.

affects: >=7.0.0

breakingIn v7, .restore() does not reset the sandbox; use .reset() to clear all routes.

fix

Use fetchMock.reset() to clear routes; use fetchMock.restore() only to remove global fetch mock.

affects: >=7.0.0

gotchafetch-mock does not polyfill fetch; you must provide a fetch implementation in Node.js (e.g., node-fetch).

fix

Install node-fetch and ensure it's available globally or import fetch from 'node-fetch' before using fetch-mock.

affects: *

deprecatedUsing .once() to limit call count is deprecated; use .mock({...}, {repeat: 1}) instead.

fix

Replace .once(url, response) with .mock(url, response, { repeat: 1 }).

affects: >=7.0.0

gotchaWhen using sandbox mode, fetchMock.restore() does not clean up the sandbox; call sandbox.restore() separately.

fix

Always call sandbox.restore() after tests if using sandbox mode.

affects: *

Errors

Common errors & fixes

TypeError: fetchMock.mock is not a function

Using an older version where fetchMock() was the main API.

fix

Update to v7 and use fetchMock.mock() or use fetchMock() in older versions.

Error: fetch is not defined

No fetch polyfill in Node.js environment.

fix

Install node-fetch and add global.fetch = require('node-fetch') at the top of your test file.

Uncaught Error: fetchMock already mocked

Attempting to call fetchMock.mock() after fetchMock.restore() has already been called.

fix

Do not call fetchMock.mock() after restore; use fetchMock.reset() to clear routes without unmocking fetch.

Upgrade

Version history

7.3.1-fork-0.1.0latest on npm

Audit

Dependencies

node-fetchoptionalRequired in Node.js environment because Node does not have a native fetch API (pre-v18).

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/One-com/fetch-mock ↗

packagefetch-mock-one.com ↗

homepagehttp://www.wheresrhys.co.uk/fetch-mock ↗