react / react/react-native

Fetch API does not support getReader (response.body is undefined)

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Description

Description

When trying to read the response from Fetch as a stream, via getReader(), I get an error saying that resp.body is undefined. Logging the value of resp shows this:

{"_bodyBlob": {"_data": {"__collector": [Object], "blobId": "xxx", "name": "chat.txt", "offset": 0, "size": 42, "type": "text/plain"}}, "_bodyInit": {"_data": {"__collector": [Object], "blobId": "xxx", "name": "chat.txt", "offset": 0, "size": 42, "type": "text/plain"}}, "bodyUsed": false, "headers": {"map": {"cache-control": "no-store", "content-length": "42", "content-type": "text/plain; charset=utf-8", "date": "Sun, 21 May 2023 18:53:09 GMT", "expect-ct": "max-age=2592000, report-uri=\"https://sentry.repl.it/api/10/security/?sentry_key=xxx\"", "replit-cluster": "hacker", "strict-transport-security": "max-age=6123043; includeSubDomains", "uwebsockets": "20"}}, "ok": true, "status": 200, "statusText": "", "type": "default", "url": "https://xxx.luisafk.repl.co/chat"}

Duplicate of #25701 and #25910, but they were closed.

React Native Version

0.71.7

Output of npx react-native info
System:
    OS: macOS 12.6.3
    CPU: (8) x64 Intel(R) Core(TM) i7-6920HQ CPU @ 2.90GHz
    Memory: 346.30 MB / 16.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 19.7.0 - ~/.nvm/versions/node/v19.7.0/bin/node
    Yarn: 1.22.15 - ~/.nvm/versions/node/v19.7.0/bin/yarn
    npm: 9.5.0 - ~/.nvm/versions/node/v19.7.0/bin/npm
    Watchman: Not Found
  Managers:
    CocoaPods: Not Found
  SDKs:
    iOS SDK: Not Found
    Android SDK: Not Found
  IDEs:
    Android Studio: Not Found
    Xcode: /undefined - /usr/bin/xcodebuild
  Languages:
    Java: Not Found
  npmPackages:
    @react-native-community/cli: Not Found
    react: 18.2.0 => 18.2.0 
    react-native: 0.71.7 => 0.71.7 
    react-native-macos: Not Found
  npmGlobalPackages:
    *react-native*: Not Found
Steps to reproduce

Try the code example below.

Snack, code example, screenshot, or link to a repository
const resp = await fetch('https://example.com');
const reader = resp.body.getReader();

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the provided fetch/getReader reproduction on React Native 0.71.7 and inspect the Fetch API response body behavior. Done means resp.body is available and resp.body.getReader() works for the reproduced response without the undefined error.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react
Domain
api, mobile
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
38/100

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