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A light-weight module that brings Fetch API to Node.js.
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- Consider supporting us on our Open Collective: -
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- A light-weight module that brings Fetch API to Node.js.
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-Promise<[Response](#class-response)>
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-Perform an HTTP(S) fetch.
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-`url` should be an absolute url, such as `https://example.com/`. A path-relative URL (`/file/under/root`) or protocol-relative URL (`//can-be-http-or-https.com/`) will result in a rejected `Promise`.
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-### Options
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-The default values are shown after each option key.
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-```js
-{
- // These properties are part of the Fetch Standard
- method: 'GET',
- headers: {}, // Request headers. format is the identical to that accepted by the Headers constructor (see below)
- body: null, // Request body. can be null, a string, a Buffer, a Blob, or a Node.js Readable stream
- redirect: 'follow', // Set to `manual` to extract redirect headers, `error` to reject redirect
- signal: null, // Pass an instance of AbortSignal to optionally abort requests
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- // The following properties are node-fetch extensions
- follow: 20, // maximum redirect count. 0 to not follow redirect
- compress: true, // support gzip/deflate content encoding. false to disable
- size: 0, // maximum response body size in bytes. 0 to disable
- agent: null, // http(s).Agent instance or function that returns an instance (see below)
- highWaterMark: 16384, // the maximum number of bytes to store in the internal buffer before ceasing to read from the underlying resource.
- insecureHTTPParser: false // Use an insecure HTTP parser that accepts invalid HTTP headers when `true`.
-}
-```
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-#### Default Headers
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-If no values are set, the following request headers will be sent automatically:
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-| Header | Value |
-| ------------------- | ------------------------------------------------------ |
-| `Accept-Encoding` | `gzip,deflate,br` _(when `options.compress === true`)_ |
-| `Accept` | `*/*` |
-| `Connection` | `close` _(when no `options.agent` is present)_ |
-| `Content-Length` | _(automatically calculated, if possible)_ |
-| `Transfer-Encoding` | `chunked` _(when `req.body` is a stream)_ |
-| `User-Agent` | `node-fetch` |
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-Note: when `body` is a `Stream`, `Content-Length` is not set automatically.
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-#### Custom Agent
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-The `agent` option allows you to specify networking related options which are out of the scope of Fetch, including and not limited to the following:
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-- Support self-signed certificate
-- Use only IPv4 or IPv6
-- Custom DNS Lookup
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-See [`http.Agent`](https://nodejs.org/api/http.html#http_new_agent_options) for more information.
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-In addition, the `agent` option accepts a function that returns `http`(s)`.Agent` instance given current [URL](https://nodejs.org/api/url.html), this is useful during a redirection chain across HTTP and HTTPS protocol.
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-```js
-const http = require('http');
-const https = require('https');
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-const httpAgent = new http.Agent({
- keepAlive: true
-});
-const httpsAgent = new https.Agent({
- keepAlive: true
-});
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-const options = {
- agent: function(_parsedURL) {
- if (_parsedURL.protocol == 'http:') {
- return httpAgent;
- } else {
- return httpsAgent;
- }
- }
-};
-```
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-#### Custom highWaterMark
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-Stream on Node.js have a smaller internal buffer size (16kB, aka `highWaterMark`) from client-side browsers (>1MB, not consistent across browsers). Because of that, when you are writing an isomorphic app and using `res.clone()`, it will hang with large response in Node.
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-The recommended way to fix this problem is to resolve cloned response in parallel:
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-```js
-const fetch = require('node-fetch');
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-const response = await fetch('https://example.com');
-const r1 = await response.clone();
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-const results = await Promise.all([response.json(), r1.text()]);
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-console.log(results[0]);
-console.log(results[1]);
-```
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-If for some reason you don't like the solution above, since `3.x` you are able to modify the `highWaterMark` option:
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-```js
-const fetch = require('node-fetch');
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-const response = await fetch('https://example.com', {
- // About 1MB
- highWaterMark: 1024 * 1024
-});
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-const result = await res.clone().buffer();
-console.dir(result);
-```
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-#### Insecure HTTP Parser
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-Passed through to the `insecureHTTPParser` option on http(s).request. See [`http.request`](https://nodejs.org/api/http.html#http_http_request_url_options_callback) for more information.
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-### Class: Request
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-An HTTP(S) request containing information about URL, method, headers, and the body. This class implements the [Body](#iface-body) interface.
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-Due to the nature of Node.js, the following properties are not implemented at this moment:
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-- `type`
-- `destination`
-- `referrer`
-- `referrerPolicy`
-- `mode`
-- `credentials`
-- `cache`
-- `integrity`
-- `keepalive`
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-The following node-fetch extension properties are provided:
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-- `follow`
-- `compress`
-- `counter`
-- `agent`
-- `highWaterMark`
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-See [options](#fetch-options) for exact meaning of these extensions.
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-#### new Request(input[, options])
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-_(spec-compliant)_
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-- `input` A string representing a URL, or another `Request` (which will be cloned)
-- `options` [Options][#fetch-options] for the HTTP(S) request
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-Constructs a new `Request` object. The constructor is identical to that in the [browser](https://developer.mozilla.org/en-US/docs/Web/API/Request/Request).
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-In most cases, directly `fetch(url, options)` is simpler than creating a `Request` object.
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-
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-### Class: Response
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-An HTTP(S) response. This class implements the [Body](#iface-body) interface.
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-The following properties are not implemented in node-fetch at this moment:
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-- `Response.error()`
-- `Response.redirect()`
-- `type`
-- `trailer`
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-#### new Response([body[, options]])
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-_(spec-compliant)_
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-- `body` A `String` or [`Readable` stream][node-readable]
-- `options` A [`ResponseInit`][response-init] options dictionary
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-Constructs a new `Response` object. The constructor is identical to that in the [browser](https://developer.mozilla.org/en-US/docs/Web/API/Response/Response).
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-Because Node.js does not implement service workers (for which this class was designed), one rarely has to construct a `Response` directly.
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-#### response.ok
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-_(spec-compliant)_
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-Convenience property representing if the request ended normally. Will evaluate to true if the response status was greater than or equal to 200 but smaller than 300.
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-#### response.redirected
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-_(spec-compliant)_
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-Convenience property representing if the request has been redirected at least once. Will evaluate to true if the internal redirect counter is greater than 0.
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-
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-### Class: Headers
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-This class allows manipulating and iterating over a set of HTTP headers. All methods specified in the [Fetch Standard][whatwg-fetch] are implemented.
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-#### new Headers([init])
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-_(spec-compliant)_
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-- `init` Optional argument to pre-fill the `Headers` object
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-Construct a new `Headers` object. `init` can be either `null`, a `Headers` object, an key-value map object or any iterable object.
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-```js
-// Example adapted from https://fetch.spec.whatwg.org/#example-headers-class
-const {Headers} = require('node-fetch');
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-const meta = {
- 'Content-Type': 'text/xml',
- 'Breaking-Bad': '<3'
-};
-const headers = new Headers(meta);
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-// The above is equivalent to
-const meta = [['Content-Type', 'text/xml'], ['Breaking-Bad', '<3']];
-const headers = new Headers(meta);
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-// You can in fact use any iterable objects, like a Map or even another Headers
-const meta = new Map();
-meta.set('Content-Type', 'text/xml');
-meta.set('Breaking-Bad', '<3');
-const headers = new Headers(meta);
-const copyOfHeaders = new Headers(headers);
-```
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-
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-### Interface: Body
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-`Body` is an abstract interface with methods that are applicable to both `Request` and `Response` classes.
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-The following methods are not yet implemented in node-fetch at this moment:
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-- `formData()`
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-#### body.body
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-_(deviation from spec)_
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-- Node.js [`Readable` stream][node-readable]
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-Data are encapsulated in the `Body` object. Note that while the [Fetch Standard][whatwg-fetch] requires the property to always be a WHATWG `ReadableStream`, in node-fetch it is a Node.js [`Readable` stream][node-readable].
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-#### body.bodyUsed
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-_(spec-compliant)_
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-- `Boolean`
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-A boolean property for if this body has been consumed. Per the specs, a consumed body cannot be used again.
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-#### body.arrayBuffer()
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-#### body.blob()
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-#### body.json()
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-#### body.text()
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-_(spec-compliant)_
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-- Returns: `Promise`
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-Consume the body and return a promise that will resolve to one of these formats.
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-#### body.buffer()
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-_(node-fetch extension)_
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-- Returns: `Promise