Stefan Hacker
45 lines
1.2 KiB
Markdown
45 lines
1.2 KiB
Markdown
# is-network-error
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> Check if a value is a [Fetch network error](https://developer.mozilla.org/en-US/docs/Web/API/fetch#exceptions)
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This can be useful when you want to do something specific when a network error happens without catching other Fetch-related errors.
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Unfortunately, Fetch network errors are [not standardized](https://github.com/whatwg/fetch/issues/526) and differ among implementations. This package handles the differences across Node.js, Bun, Deno, and browsers.
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For instance, [`p-retry`](https://github.com/sindresorhus/p-retry) uses this package to retry on network errors.
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## Install
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```sh
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npm install is-network-error
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```
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## Usage
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```js
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import isNetworkError from 'is-network-error';
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async function getUnicorns() {
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try {
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const response = await fetch('unicorns.json');
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return await response.json();
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} catch (error) {
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if (isNetworkError(error)) {
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return localStorage.getItem('…');
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}
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throw error;
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}
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}
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console.log(await getUnicorns());
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```
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## API
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### `isNetworkError(value: unknown): value is TypeError`
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Returns `true` if the given value is a Fetch network error, otherwise `false`.
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This function acts as a type guard, narrowing the type to `TypeError` when it returns `true`.
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