Silent failure with `null` header value

[dylanpyle]

Requests appear to silently fail when a header value is null.

This code works fine:

const headers = {
  'Content-Type': 'multipart/form-data'
};

const files = [
  {
    name: 'image',
    filename: 'image.jpg',
    type: 'image/jpeg',
    data: RNFetchBlob.wrap(filePath)
  }
];

RNFetchBlob.fetch('POST', url, headers, files)
  .then((response) => { console.log('response: ', response); })
  .catch((err) => { console.log('error: ', err); });

This code silently fails, and neither resolves or rejects:

const headers = {
  'Content-Type': 'multipart/form-data',
  Authorization: null
};

const files = [
  {
    name: 'image',
    filename: 'image.jpg',
    type: 'image/jpeg',
    data: RNFetchBlob.wrap(filePath)
  }
];

RNFetchBlob.fetch('POST', url, headers, files)
  .then((response) => { console.log('response: ', response); })
  .catch((err) => { console.log('error: ', err); });

Using

"react-native-fetch-blob": "0.10.2-beta.1",
"react-native": "0.39.2",

[wkh237]

@dylanpyle , I've noticed this may due to that our native code does not handle empty header value well, I've added some handling in 0.10.2-beta.8 which will substitute null and undefined headers with an empty string. Please try upgrade you package and see if that works.