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diff --git a/lib/fetch/response.js b/lib/fetch/response.js
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+++ b/lib/fetch/response.js
@@ -0,0 +1,571 @@
+'use strict'
+
+const { Headers, HeadersList, fill } = require('./headers')
+const { extractBody, cloneBody, mixinBody } = require('./body')
+const util = require('../core/util')
+const { kEnumerableProperty } = util
+const {
+  isValidReasonPhrase,
+  isCancelled,
+  isAborted,
+  isBlobLike,
+  serializeJavascriptValueToJSONString,
+  isErrorLike,
+  isomorphicEncode
+} = require('./util')
+const {
+  redirectStatusSet,
+  nullBodyStatus,
+  DOMException
+} = require('./constants')
+const { kState, kHeaders, kGuard, kRealm } = require('./symbols')
+const { webidl } = require('./webidl')
+const { FormData } = require('./formdata')
+const { getGlobalOrigin } = require('./global')
+const { URLSerializer } = require('./dataURL')
+const { kHeadersList, kConstruct } = require('../core/symbols')
+const assert = require('assert')
+const { types } = require('util')
+
+const ReadableStream = globalThis.ReadableStream || require('stream/web').ReadableStream
+const textEncoder = new TextEncoder('utf-8')
+
+// https://fetch.spec.whatwg.org/#response-class
+class Response {
+  // Creates network error Response.
+  static error () {
+    // TODO
+    const relevantRealm = { settingsObject: {} }
+
+    // The static error() method steps are to return the result of creating a
+    // Response object, given a new network error, "immutable", and this’s
+    // relevant Realm.
+    const responseObject = new Response()
+    responseObject[kState] = makeNetworkError()
+    responseObject[kRealm] = relevantRealm
+    responseObject[kHeaders][kHeadersList] = responseObject[kState].headersList
+    responseObject[kHeaders][kGuard] = 'immutable'
+    responseObject[kHeaders][kRealm] = relevantRealm
+    return responseObject
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-response-json
+  static json (data, init = {}) {
+    webidl.argumentLengthCheck(arguments, 1, { header: 'Response.json' })
+
+    if (init !== null) {
+      init = webidl.converters.ResponseInit(init)
+    }
+
+    // 1. Let bytes the result of running serialize a JavaScript value to JSON bytes on data.
+    const bytes = textEncoder.encode(
+      serializeJavascriptValueToJSONString(data)
+    )
+
+    // 2. Let body be the result of extracting bytes.
+    const body = extractBody(bytes)
+
+    // 3. Let responseObject be the result of creating a Response object, given a new response,
+    //    "response", and this’s relevant Realm.
+    const relevantRealm = { settingsObject: {} }
+    const responseObject = new Response()
+    responseObject[kRealm] = relevantRealm
+    responseObject[kHeaders][kGuard] = 'response'
+    responseObject[kHeaders][kRealm] = relevantRealm
+
+    // 4. Perform initialize a response given responseObject, init, and (body, "application/json").
+    initializeResponse(responseObject, init, { body: body[0], type: 'application/json' })
+
+    // 5. Return responseObject.
+    return responseObject
+  }
+
+  // Creates a redirect Response that redirects to url with status status.
+  static redirect (url, status = 302) {
+    const relevantRealm = { settingsObject: {} }
+
+    webidl.argumentLengthCheck(arguments, 1, { header: 'Response.redirect' })
+
+    url = webidl.converters.USVString(url)
+    status = webidl.converters['unsigned short'](status)
+
+    // 1. Let parsedURL be the result of parsing url with current settings
+    // object’s API base URL.
+    // 2. If parsedURL is failure, then throw a TypeError.
+    // TODO: base-URL?
+    let parsedURL
+    try {
+      parsedURL = new URL(url, getGlobalOrigin())
+    } catch (err) {
+      throw Object.assign(new TypeError('Failed to parse URL from ' + url), {
+        cause: err
+      })
+    }
+
+    // 3. If status is not a redirect status, then throw a RangeError.
+    if (!redirectStatusSet.has(status)) {
+      throw new RangeError('Invalid status code ' + status)
+    }
+
+    // 4. Let responseObject be the result of creating a Response object,
+    // given a new response, "immutable", and this’s relevant Realm.
+    const responseObject = new Response()
+    responseObject[kRealm] = relevantRealm
+    responseObject[kHeaders][kGuard] = 'immutable'
+    responseObject[kHeaders][kRealm] = relevantRealm
+
+    // 5. Set responseObject’s response’s status to status.
+    responseObject[kState].status = status
+
+    // 6. Let value be parsedURL, serialized and isomorphic encoded.
+    const value = isomorphicEncode(URLSerializer(parsedURL))
+
+    // 7. Append `Location`/value to responseObject’s response’s header list.
+    responseObject[kState].headersList.append('location', value)
+
+    // 8. Return responseObject.
+    return responseObject
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-response
+  constructor (body = null, init = {}) {
+    if (body !== null) {
+      body = webidl.converters.BodyInit(body)
+    }
+
+    init = webidl.converters.ResponseInit(init)
+
+    // TODO
+    this[kRealm] = { settingsObject: {} }
+
+    // 1. Set this’s response to a new response.
+    this[kState] = makeResponse({})
+
+    // 2. Set this’s headers to a new Headers object with this’s relevant
+    // Realm, whose header list is this’s response’s header list and guard
+    // is "response".
+    this[kHeaders] = new Headers(kConstruct)
+    this[kHeaders][kGuard] = 'response'
+    this[kHeaders][kHeadersList] = this[kState].headersList
+    this[kHeaders][kRealm] = this[kRealm]
+
+    // 3. Let bodyWithType be null.
+    let bodyWithType = null
+
+    // 4. If body is non-null, then set bodyWithType to the result of extracting body.
+    if (body != null) {
+      const [extractedBody, type] = extractBody(body)
+      bodyWithType = { body: extractedBody, type }
+    }
+
+    // 5. Perform initialize a response given this, init, and bodyWithType.
+    initializeResponse(this, init, bodyWithType)
+  }
+
+  // Returns response’s type, e.g., "cors".
+  get type () {
+    webidl.brandCheck(this, Response)
+
+    // The type getter steps are to return this’s response’s type.
+    return this[kState].type
+  }
+
+  // Returns response’s URL, if it has one; otherwise the empty string.
+  get url () {
+    webidl.brandCheck(this, Response)
+
+    const urlList = this[kState].urlList
+
+    // The url getter steps are to return the empty string if this’s
+    // response’s URL is null; otherwise this’s response’s URL,
+    // serialized with exclude fragment set to true.
+    const url = urlList[urlList.length - 1] ?? null
+
+    if (url === null) {
+      return ''
+    }
+
+    return URLSerializer(url, true)
+  }
+
+  // Returns whether response was obtained through a redirect.
+  get redirected () {
+    webidl.brandCheck(this, Response)
+
+    // The redirected getter steps are to return true if this’s response’s URL
+    // list has more than one item; otherwise false.
+    return this[kState].urlList.length > 1
+  }
+
+  // Returns response’s status.
+  get status () {
+    webidl.brandCheck(this, Response)
+
+    // The status getter steps are to return this’s response’s status.
+    return this[kState].status
+  }
+
+  // Returns whether response’s status is an ok status.
+  get ok () {
+    webidl.brandCheck(this, Response)
+
+    // The ok getter steps are to return true if this’s response’s status is an
+    // ok status; otherwise false.
+    return this[kState].status >= 200 && this[kState].status <= 299
+  }
+
+  // Returns response’s status message.
+  get statusText () {
+    webidl.brandCheck(this, Response)
+
+    // The statusText getter steps are to return this’s response’s status
+    // message.
+    return this[kState].statusText
+  }
+
+  // Returns response’s headers as Headers.
+  get headers () {
+    webidl.brandCheck(this, Response)
+
+    // The headers getter steps are to return this’s headers.
+    return this[kHeaders]
+  }
+
+  get body () {
+    webidl.brandCheck(this, Response)
+
+    return this[kState].body ? this[kState].body.stream : null
+  }
+
+  get bodyUsed () {
+    webidl.brandCheck(this, Response)
+
+    return !!this[kState].body && util.isDisturbed(this[kState].body.stream)
+  }
+
+  // Returns a clone of response.
+  clone () {
+    webidl.brandCheck(this, Response)
+
+    // 1. If this is unusable, then throw a TypeError.
+    if (this.bodyUsed || (this.body && this.body.locked)) {
+      throw webidl.errors.exception({
+        header: 'Response.clone',
+        message: 'Body has already been consumed.'
+      })
+    }
+
+    // 2. Let clonedResponse be the result of cloning this’s response.
+    const clonedResponse = cloneResponse(this[kState])
+
+    // 3. Return the result of creating a Response object, given
+    // clonedResponse, this’s headers’s guard, and this’s relevant Realm.
+    const clonedResponseObject = new Response()
+    clonedResponseObject[kState] = clonedResponse
+    clonedResponseObject[kRealm] = this[kRealm]
+    clonedResponseObject[kHeaders][kHeadersList] = clonedResponse.headersList
+    clonedResponseObject[kHeaders][kGuard] = this[kHeaders][kGuard]
+    clonedResponseObject[kHeaders][kRealm] = this[kHeaders][kRealm]
+
+    return clonedResponseObject
+  }
+}
+
+mixinBody(Response)
+
+Object.defineProperties(Response.prototype, {
+  type: kEnumerableProperty,
+  url: kEnumerableProperty,
+  status: kEnumerableProperty,
+  ok: kEnumerableProperty,
+  redirected: kEnumerableProperty,
+  statusText: kEnumerableProperty,
+  headers: kEnumerableProperty,
+  clone: kEnumerableProperty,
+  body: kEnumerableProperty,
+  bodyUsed: kEnumerableProperty,
+  [Symbol.toStringTag]: {
+    value: 'Response',
+    configurable: true
+  }
+})
+
+Object.defineProperties(Response, {
+  json: kEnumerableProperty,
+  redirect: kEnumerableProperty,
+  error: kEnumerableProperty
+})
+
+// https://fetch.spec.whatwg.org/#concept-response-clone
+function cloneResponse (response) {
+  // To clone a response response, run these steps:
+
+  // 1. If response is a filtered response, then return a new identical
+  // filtered response whose internal response is a clone of response’s
+  // internal response.
+  if (response.internalResponse) {
+    return filterResponse(
+      cloneResponse(response.internalResponse),
+      response.type
+    )
+  }
+
+  // 2. Let newResponse be a copy of response, except for its body.
+  const newResponse = makeResponse({ ...response, body: null })
+
+  // 3. If response’s body is non-null, then set newResponse’s body to the
+  // result of cloning response’s body.
+  if (response.body != null) {
+    newResponse.body = cloneBody(response.body)
+  }
+
+  // 4. Return newResponse.
+  return newResponse
+}
+
+function makeResponse (init) {
+  return {
+    aborted: false,
+    rangeRequested: false,
+    timingAllowPassed: false,
+    requestIncludesCredentials: false,
+    type: 'default',
+    status: 200,
+    timingInfo: null,
+    cacheState: '',
+    statusText: '',
+    ...init,
+    headersList: init.headersList
+      ? new HeadersList(init.headersList)
+      : new HeadersList(),
+    urlList: init.urlList ? [...init.urlList] : []
+  }
+}
+
+function makeNetworkError (reason) {
+  const isError = isErrorLike(reason)
+  return makeResponse({
+    type: 'error',
+    status: 0,
+    error: isError
+      ? reason
+      : new Error(reason ? String(reason) : reason),
+    aborted: reason && reason.name === 'AbortError'
+  })
+}
+
+function makeFilteredResponse (response, state) {
+  state = {
+    internalResponse: response,
+    ...state
+  }
+
+  return new Proxy(response, {
+    get (target, p) {
+      return p in state ? state[p] : target[p]
+    },
+    set (target, p, value) {
+      assert(!(p in state))
+      target[p] = value
+      return true
+    }
+  })
+}
+
+// https://fetch.spec.whatwg.org/#concept-filtered-response
+function filterResponse (response, type) {
+  // Set response to the following filtered response with response as its
+  // internal response, depending on request’s response tainting:
+  if (type === 'basic') {
+    // A basic filtered response is a filtered response whose type is "basic"
+    // and header list excludes any headers in internal response’s header list
+    // whose name is a forbidden response-header name.
+
+    // Note: undici does not implement forbidden response-header names
+    return makeFilteredResponse(response, {
+      type: 'basic',
+      headersList: response.headersList
+    })
+  } else if (type === 'cors') {
+    // A CORS filtered response is a filtered response whose type is "cors"
+    // and header list excludes any headers in internal response’s header
+    // list whose name is not a CORS-safelisted response-header name, given
+    // internal response’s CORS-exposed header-name list.
+
+    // Note: undici does not implement CORS-safelisted response-header names
+    return makeFilteredResponse(response, {
+      type: 'cors',
+      headersList: response.headersList
+    })
+  } else if (type === 'opaque') {
+    // An opaque filtered response is a filtered response whose type is
+    // "opaque", URL list is the empty list, status is 0, status message
+    // is the empty byte sequence, header list is empty, and body is null.
+
+    return makeFilteredResponse(response, {
+      type: 'opaque',
+      urlList: Object.freeze([]),
+      status: 0,
+      statusText: '',
+      body: null
+    })
+  } else if (type === 'opaqueredirect') {
+    // An opaque-redirect filtered response is a filtered response whose type
+    // is "opaqueredirect", status is 0, status message is the empty byte
+    // sequence, header list is empty, and body is null.
+
+    return makeFilteredResponse(response, {
+      type: 'opaqueredirect',
+      status: 0,
+      statusText: '',
+      headersList: [],
+      body: null
+    })
+  } else {
+    assert(false)
+  }
+}
+
+// https://fetch.spec.whatwg.org/#appropriate-network-error
+function makeAppropriateNetworkError (fetchParams, err = null) {
+  // 1. Assert: fetchParams is canceled.
+  assert(isCancelled(fetchParams))
+
+  // 2. Return an aborted network error if fetchParams is aborted;
+  // otherwise return a network error.
+  return isAborted(fetchParams)
+    ? makeNetworkError(Object.assign(new DOMException('The operation was aborted.', 'AbortError'), { cause: err }))
+    : makeNetworkError(Object.assign(new DOMException('Request was cancelled.'), { cause: err }))
+}
+
+// https://whatpr.org/fetch/1392.html#initialize-a-response
+function initializeResponse (response, init, body) {
+  // 1. If init["status"] is not in the range 200 to 599, inclusive, then
+  //    throw a RangeError.
+  if (init.status !== null && (init.status < 200 || init.status > 599)) {
+    throw new RangeError('init["status"] must be in the range of 200 to 599, inclusive.')
+  }
+
+  // 2. If init["statusText"] does not match the reason-phrase token production,
+  //    then throw a TypeError.
+  if ('statusText' in init && init.statusText != null) {
+    // See, https://datatracker.ietf.org/doc/html/rfc7230#section-3.1.2:
+    //   reason-phrase  = *( HTAB / SP / VCHAR / obs-text )
+    if (!isValidReasonPhrase(String(init.statusText))) {
+      throw new TypeError('Invalid statusText')
+    }
+  }
+
+  // 3. Set response’s response’s status to init["status"].
+  if ('status' in init && init.status != null) {
+    response[kState].status = init.status
+  }
+
+  // 4. Set response’s response’s status message to init["statusText"].
+  if ('statusText' in init && init.statusText != null) {
+    response[kState].statusText = init.statusText
+  }
+
+  // 5. If init["headers"] exists, then fill response’s headers with init["headers"].
+  if ('headers' in init && init.headers != null) {
+    fill(response[kHeaders], init.headers)
+  }
+
+  // 6. If body was given, then:
+  if (body) {
+    // 1. If response's status is a null body status, then throw a TypeError.
+    if (nullBodyStatus.includes(response.status)) {
+      throw webidl.errors.exception({
+        header: 'Response constructor',
+        message: 'Invalid response status code ' + response.status
+      })
+    }
+
+    // 2. Set response's body to body's body.
+    response[kState].body = body.body
+
+    // 3. If body's type is non-null and response's header list does not contain
+    //    `Content-Type`, then append (`Content-Type`, body's type) to response's header list.
+    if (body.type != null && !response[kState].headersList.contains('Content-Type')) {
+      response[kState].headersList.append('content-type', body.type)
+    }
+  }
+}
+
+webidl.converters.ReadableStream = webidl.interfaceConverter(
+  ReadableStream
+)
+
+webidl.converters.FormData = webidl.interfaceConverter(
+  FormData
+)
+
+webidl.converters.URLSearchParams = webidl.interfaceConverter(
+  URLSearchParams
+)
+
+// https://fetch.spec.whatwg.org/#typedefdef-xmlhttprequestbodyinit
+webidl.converters.XMLHttpRequestBodyInit = function (V) {
+  if (typeof V === 'string') {
+    return webidl.converters.USVString(V)
+  }
+
+  if (isBlobLike(V)) {
+    return webidl.converters.Blob(V, { strict: false })
+  }
+
+  if (types.isArrayBuffer(V) || types.isTypedArray(V) || types.isDataView(V)) {
+    return webidl.converters.BufferSource(V)
+  }
+
+  if (util.isFormDataLike(V)) {
+    return webidl.converters.FormData(V, { strict: false })
+  }
+
+  if (V instanceof URLSearchParams) {
+    return webidl.converters.URLSearchParams(V)
+  }
+
+  return webidl.converters.DOMString(V)
+}
+
+// https://fetch.spec.whatwg.org/#bodyinit
+webidl.converters.BodyInit = function (V) {
+  if (V instanceof ReadableStream) {
+    return webidl.converters.ReadableStream(V)
+  }
+
+  // Note: the spec doesn't include async iterables,
+  // this is an undici extension.
+  if (V?.[Symbol.asyncIterator]) {
+    return V
+  }
+
+  return webidl.converters.XMLHttpRequestBodyInit(V)
+}
+
+webidl.converters.ResponseInit = webidl.dictionaryConverter([
+  {
+    key: 'status',
+    converter: webidl.converters['unsigned short'],
+    defaultValue: 200
+  },
+  {
+    key: 'statusText',
+    converter: webidl.converters.ByteString,
+    defaultValue: ''
+  },
+  {
+    key: 'headers',
+    converter: webidl.converters.HeadersInit
+  }
+])
+
+module.exports = {
+  makeNetworkError,
+  makeResponse,
+  makeAppropriateNetworkError,
+  filterResponse,
+  Response,
+  cloneResponse
+}