fetch needs patched for try/catch on JSON.parse

[niftylettuce]

Please fix

react-native/Libraries/Fetch/fetch.js

Line 232 in 854689d

return this.text().then(JSON.parse)

to have try/catch surrounding JSON.parse?

[niftylettuce]

also why are you throwing errors instead of sending them back with Promise.reject?

react-native/Libraries/Fetch/fetch.js

Line 125 in 854689d

return Promise.reject(new TypeError('Already read'))

uses reject but this doesn't

react-native/Libraries/Fetch/fetch.js

Line 194 in 854689d

throw new Error('could not read FormData body as blob')

[niftylettuce]

Basically because you are throwing errors and not wrapping JSON.parse in a try/catch block - I had to dig deep to find out that my 404 response could not use res.json() in this example:

        fetch(apiUri + path, {
          method: 'GET',
          headers: that.headers
        })
        .then((res) => res.json())
        .then((res) => {
          if (res && res.error)
            return fn(res.error);
          fn(null, res);
        })
        .catch(fn)

The error is thrown that it can't parse JSON (the body is text response)

[niftylettuce]

The reason I have to use fetch polyfill is because superagent doesn't work (because it's trying to run in a node runtime environment and not a browser environment or something). This is broken and we can't even hook in a simple API into react-native...

[satya164]

if an error is thrown inside the .then callback, isn't it supposed to be propagated to the .catch callback?

[facebook-github-bot]

Hey niftylettuce, thanks for reporting this issue!

React Native, as you've probably heard, is getting really popular and truth is we're getting a bit overwhelmed by the activity surrounding it. There are just too many issues for us to manage properly.

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[brentvatne]

Closing as per discussion in JakeChampion/fetch#235