UnhandledPromiseRejectionWarning in result.js

[Steffen93]

Hi,
I'm using the npm package of this neo4j driver in my nodejs application (Node version 7.4.0) and I'm getting the following warning all the time:

(node:11241) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: Cannot read property 'call' of undefined

The warning still appears in the current git version, I just cloned the repo and tested it.
It seems like in result.js in the lines 119 and 132, there is no 'catch' for the promises called there and that's why the warning is spit out by node (if your node version is 6.6.0+).

Changing

    self._connectionHolder.releaseConnection().then(() => {
        onCompletedOriginal.call(observer, sum);
    });

to

    self._connectionHolder.releaseConnection().then(() => {
        onCompletedOriginal.call(observer, sum);
    }).catch(() => {} );

removes the warning for me (tested locally), but I don't know if there is further error handling to do in the catch.

[lutovich]

Hi @Steffen93,

Thanks for reporting this problem.
Could you please try fix from #258?

I believe problem you are seeing is related to absence of "default" value for onCompleted callback in the given observer.

[Steffen93]

Hi @lutovich,
I can confirm that the issue is fixed for me.
One more thing, in the README.md it says to use npm build to build locally, while it is npm run build actually. It's just a bit confusing since npm build is still a valid command but doesn't do anything, maybe you can update that some day.

Anyway thanks for the quick fix!