Guard against empty or unparseable WeatherUnderground responses (#154)

[7onnie]

Problem

With the WeatherUnderground API selected, the plugin intermittently logs SyntaxError: Unexpected end of JSON input and the update cycle silently reports an empty weather object instead of skipping the failed poll.

Root cause

apis/weatherunderground.js relies on axios to parse the response body as JSON. When WeatherUnderground returns a truncated or otherwise unparseable 200 body, axios's transformResponse silently swallows the JSON.parse failure and leaves response.data as a non-empty string. The old guard if (response.data) is truthy for that string, so the code proceeds into parseReport(...) on a string, throws internally, returns {} and ends up calling callback(null, { report: {} }) — a bogus successful empty update.

Fix

Tighten the guard to require an actual parsed object:

if (response.data && typeof response.data === 'object') { ... }
else { /* report a clear error and skip this cycle */ }

Unparseable/truncated responses now take the error branch. The caller (index.js) already gates on !error, so the cycle is skipped cleanly with no characteristic writes — no stale or zeroed values.

Validation (no hardware required)

Drove the real WundergroundAPI.update() against mock HTTP servers:

Response	Before	After
valid 200 JSON	normal report	normal report (unchanged)
truncated 200 body	callback(null, {report:{}}) (bogus success)	callback(error), cycle skipped
empty 200 body	already handled	callback(error)

node --check passes (repo has no build/lint/test scripts). No secrets in the diff.

Notes

• Empty bodies were already handled (axios leaves an empty 200 as '', falsy) — the new behaviour specifically covers the truncated/unparseable-but-non-empty case.
• Likely the same root cause behind API- Fehler Weather Underground #310.

Fixes #154