How to add header for apollo client in react native application

createUploadLink has a headers property which matches to createHttpLink headers property.

headers: an object representing values to be sent as headers on the request

Sample

const token = await AsyncStorage.getItem('auth.token')

const client = new ApolloClient({
  link: createUploadLink({
    uri: 'http://localhost:3000/graphql',
    headers: {
      "Some-Custom-Header": token
    }
  }),
  cache: new InMemoryCache()
})

UPDATE

const getToken = async () => {
  const token = await AsyncStorage.getItem('auth.token')
  return token
}
const token = getToken()
// Initiate apollo client
const client = new ApolloClient({
  link: createUploadLink({
    uri: 'http://localhost:3000/graphql',
    headers: {
      authorization: token
    }
  }),
  cache: new InMemoryCache()
})
// Wrap apollo provider
const withProvider = (Component, client) => {
  return class extends React.Component {
    render () {
      return (
        <ApolloProvider client={client}>
          <Component {...this.props} client={client} />
        </ApolloProvider>
      )
    }
  }
}

export default async () => {
  Navigation.registerComponent('MainScreen', () => withProvider(MainScreen, client))

  Navigation.startSingleScreenApp({
    screen: {
      screen: 'MainScreen'
    }
  })
}

I am using apollo boost, What I did was,

import ApolloClient from 'apollo-boost';

const client = new ApolloClient({
  uri: 'http://localhost:3000/graphql',
  request: async (operation) => {
    const token = await AsyncStorage.getItem('token');
    operation.setContext({
      headers: {
        authorization: token
      }
    });
  }
}