is-network-error

library1.3.2jsnpmunverified

Detect Fetch network errors across Node.js, Bun, Deno, and browsers. v1.3.2 – stable, low release cadence. Unlike manual checks (e.g., error.message.includes('fetch')), it handles the non-standardized error differences across runtimes. Useful for conditional retry logic or fallback handling in fetch-based code. Written in TypeScript, ships type definitions. Requires Node >=16. Minimal, zero-dependency package.

testing

npm install is-network-error

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · IS-NETWORK-ERROR

is-network-error

testingjavascriptv1.3.2

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.

isNetworkError

✓ import isNetworkError from 'is-network-error'

✗ const isNetworkError = require('is-network-error')

ESM-only package; CJS require() will fail. Use dynamic import() if needed in CJS.

isNetworkError (type import)

✓ import type isNetworkError from 'is-network-error'

✗ import { isNetworkError } from 'is-network-error'

Named import is incorrect because the package exports a default function only. Type import is optional–you can just import the value.

isNetworkError (dynamic import)

✓ const { default: isNetworkError } = await import('is-network-error')

✗ const isNetworkError = await import('is-network-error')

Dynamic import returns a module object; the default is on .default.

Shows how to use isNetworkError to distinguish fetch network errors from other errors and implement fallback logic.

import isNetworkError from 'is-network-error'; async function fetchWithFallback() { try { const res = await fetch('https://example.com/data.json'); return res.json(); } catch (error) { if (isNetworkError(error)) { // Network error, use fallback console.log('Network error, using cached data'); return { fallback: true }; } throw error; // Re-throw non-network errors } } fetchWithFallback().then(console.log).catch(console.error);

Debug

Known issues

breakingv1.0.0 dropped CJS support; package is ESM-only. Node.js <16 not supported.

fix

Use Node >=16 and ESM imports, or use dynamic import() in CJS.

affects: >=1.0.0

gotchaThe function checks for Fetch network errors only; it will return false for other TypeError instances (e.g., JSON.parse errors).

fix

Ensure you only pass errors from fetch() calls.

affects: >=0.1.0

deprecatedVersions <1.0.0 used a different API (e.g., named exports). Upgrade to v1 for default export.

fix

Update import to default import: `import isNetworkError from 'is-network-error'`

affects: <1.0.0

Errors

Common errors & fixes

SyntaxError: Cannot use import statement outside a module

Using ESM import in a CommonJS (CJS) file without enabling ESM.

fix

Add 'type': 'module' in your package.json or rename the file to .mjs, or use dynamic import(): `const { default: isNetworkError } = await import('is-network-error')`

ERR_REQUIRE_ESM: require() of ES Module /path/to/node_modules/is-network-error/index.js from /path/to/project/index.js not supported.

Attempting to require() an ESM-only package.

fix

Use dynamic import() or switch to ESM in your project.

TypeError: isNetworkError is not a function

Named import instead of default import.

fix

Use `import isNetworkError from 'is-network-error'` (default import) not `import { isNetworkError } from 'is-network-error'`.

Upgrade

Version history

1.3.2latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

15 hits · last 30 days

node

Resources

githubhttps://github.com/sindresorhus/is-network-error ↗

packageis-network-error ↗

homepagehttps://github.com/sindresorhus/is-network-error#readme ↗