React Native fetch a local server using a proxy

Question

In my react native app I am trying to perform a fetch to my local backend server. In my package.json I have put "proxy": "http://localhost:3000" .

My fetch looks like

fetch('/')
  .then(response => response.json())
  .then(json => console.log(json))
  .catch(err => console.log)

It catches an error

[TypeError: Network request failed]

---

When I remove the proxy and manually enter the address in the fetch it works and my server receives a GET request.

fetch('http://localhost:3000')
  .then(response => response.json())
  .then(json => console.log(json))
  .catch(err => console.log)

Answer 1

Two points here:

• Set proxy in package.json is a feature of create-react-app, which wraps webpack dev server's proxy. react-native uses Metro instead of Webpack as bundler and it does not support setting up a local proxy.

• Different from the web, http client in react-native has no current host. So if you use fetch('/'), it won't know which domain or ip address to send request to.