undici implements the WHATWG Fetch Standard, providing fetch() together\nwith the Request, Response, Headers, and FormData classes that mirror\nthe browser APIs. The implementation follows the standard, so the\nMDN Fetch documentation applies as well.
import { fetch, Request, Response, Headers, FormData } from 'undici'\n\nconst response = await fetch('https://example.com')\nconst text = await response.text()\nWhen mixing these classes, keep them from the same implementation: use the\nglobal fetch() with the global FormData, Request, Response, and\nHeaders, and use undici's fetch() with undici's classes. Passing a value\ncreated by one implementation to the other can throw.
Starts the process of fetching a resource from the network and returns a\npromise that fulfills with a <Response>. The promise rejects only on network\nfailures; an HTTP error status such as 404 still fulfills the promise, so\ninspect response.ok to detect failures.
import { fetch } from 'undici'\n\nconst response = await fetch('https://example.com', {\n method: 'POST',\n headers: { 'content-type': 'application/json' },\n body: JSON.stringify({ hello: 'world' }),\n})\n\nconsole.log(response.status)\nconsole.log(await response.json())\nTo route the request through a custom <Dispatcher> (for example a ProxyAgent\nor Agent with specific options), pass it as init.dispatcher.
import { fetch, Agent } from 'undici'\n\nconst response = await fetch('https://example.com', {\n dispatcher: new Agent({ connect: { rejectUnauthorized: false } }),\n})\nA set of key/value pairs representing form fields and their values, suitable\nfor use as a fetch() request body. The implementation follows the\nWHATWG Fetch Standard; see the MDN FormData documentation.
When using FormData as a request body, keep fetch and FormData from the\nsame implementation: use the global FormData with the global fetch(), and\nundici's FormData with undici's fetch().
Creates a new, empty FormData instance. Passing any argument other than\nundefined throws; in particular, an HTMLFormElement argument is not\nsupported in this environment.
Appends a new value to an existing key, or adds the key if it does not exist.\nUnlike formData.set(), append() keeps\nany existing values for name.
Deletes all values associated with name.
Sets a new value for an existing key, or adds the key if it does not exist,\nreplacing any values previously associated with name.
<BodyMixin>Represents the response to a request. Instances are typically obtained by\nawaiting fetch(), but can also be constructed directly. The implementation\nfollows the WHATWG Fetch Standard; see the\nMDN Response documentation. Response inherits the body-reading methods\ndescribed in Body mixin.
Creates a new Response.
Returns a new Response representing a network error, with its\ntype set to 'error'.
import { Response } from 'undici'\n\nconst response = Response.json({ ok: true }, { status: 201 })\nCreates a clone of the response. Throws a TypeError if the body has already\nbeen read or is locked.
<BodyMixin>Represents a resource request. Instances can be passed to fetch() in place\nof a URL string. The implementation follows the WHATWG Fetch Standard; see\nthe MDN Request documentation. Request inherits the body-reading\nmethods described in Body mixin.
Creates a new Request.
Creates a clone of the request. Throws a TypeError if the body has already\nbeen read or is locked.
Represents the header list of a request or response and provides methods to\nread and modify it. The implementation follows the WHATWG Fetch Standard;\nsee the MDN Headers documentation. Headers is iterable, yielding\n[name, value] pairs sorted by name.
Creates a new Headers object.
Appends a value to a header, or adds the header if it does not exist. Existing\nvalues for name are preserved.
Removes the header named name.
Sets a header to a single value, replacing any existing values for name.
Returns each Set-Cookie header as a separate string, without combining them.
Request and Response both extend <BodyMixin>, which provides methods and\nproperties for reading a body. Each consuming method reads the body once; after\nthe body has been consumed, bodyUsed becomes true and\ncalling another consuming method throws a TypeError.
Buffers and parses the entire body as multipart/form-data or\napplication/x-www-form-urlencoded. Because multipart parsing has inherent\nsecurity risks and the whole body is buffered, this method must only be called\non responses from trusted servers.
For responses from untrusted or user-controlled servers, use a dedicated\nstreaming parser such as @fastify/busboy and apply application-specific\nlimits:
\nimport { Busboy } from '@fastify/busboy'\nimport { Readable } from 'node:stream'\n\nconst response = await fetch('...')\nconst busboy = new Busboy({\n headers: { 'content-type': response.headers.get('content-type') },\n})\n\n// Handle the events emitted by `busboy`.\n\nReadable.fromWeb(response.body).pipe(busboy)\nAn undici-specific extension that exposes the body as a stream of decoded text\nchunks rather than buffering it. It is not part of the WHATWG Fetch\nStandard.
" } ], "properties": [ { "textRaw": "Type: {ReadableStream|null} The body as a {ReadableStream}, or `null` if the message has no body.", "name": "body", "type": "ReadableStream|null", "meta": { "added": [ "v1.0.0" ], "changes": [] }, "desc": "The body as a {ReadableStream}, or `null` if the message has no body." }, { "textRaw": "Type: {boolean} `true` once the body has been read.", "name": "bodyUsed", "type": "boolean", "meta": { "added": [ "v1.0.0" ], "changes": [] }, "desc": "`true` once the body has been read." } ], "displayName": "Body mixin" } ] } ] }