Handling failed runs

[rgbkrk]

I'm doing something where I'm running N spawn to see if a command is available in an environment. I want to collect results of only those spawned processes that return an exit code of 0. I don't want to let the error bubble up, so I end up doing the whole catch -> Observable.empty thing.

function ipyKernelCheck(env) {
  const executable = path.join(env.prefix, 'bin', 'python');
  return spawn(executable, ['-m', 'ipykernel', '--version'], { split: true })
    .filter(x => x.source && x.source === 'stdout')
    .mapTo(env)
    .catch(err => Rx.Observable.empty());
}

If I could use the return code and squash the error I could. Should I fix something with my approach here or is there something worth exposing in spawn-rx?

[anaisbetts]

I think the catch is fine, I don't think it's a good idea to add a like, ignoreFailures parameter or something

[anaisbetts]

If you wanted to aggregate it you could do something like:

commandsToExecute
  .map({cmd, params} => spawn(cmd, params)
    .reduce((acc,x) => acc += x, '')
    .catch(() => Observable.empty()))
  .mergeAll(4 /* at a time */);

(coding via text area, not actually tested 😄 )