[Bug] Weather module handling of absent precipitationLastHour value

[davidrea]

Environment

MagicMirror² version: 2.32.0
Node version: 22.14.0
npm version: 10.9.2
Platform:

0|MagicMirror  | ### SYSTEM:   manufacturer: Raspberry Pi Foundation; model: Raspberry Pi 4 Model B Rev 1.5; virtual: false
0|MagicMirror  | ### OS:       platform: linux; distro: Debian GNU/Linux; release: 12; arch: arm64; kernel: 6.12.34+rpt-rpi-v8
0|MagicMirror  | ### VERSIONS: electron: 36.7.3; used node: 22.14.0; installed node: 22.14.0; npm: 10.9.2; pm2: 6.0.8
0|MagicMirror  | ### OTHER:    timeZone: America/New_York; ELECTRON_ENABLE_GPU: undefined

Which start option are you using?

node --run start:x11

Are you using PM2?

Yes

Module

weather

Have you tried disabling other modules?

• Yes
• No

Have you searched if someone else has already reported the issue on the forum or in the issues?

• Yes

What did you do?

Configuration

{
        module: "weather",
        position: "top_center",
        config: {
                weatherProvider: "weathergov",
                type: "current",
                lat: 43,
                lon: -77,
                roundTemp: true
        }
},

The weather module's "current" display type fails with "Loading..." displayed on-screen when api.weather.gov returns station conditions with a missing key...

currentWeather.precipitationAmount = currentWeatherData.precipitationLastHour.value ? currentWeatherData.precipitationLastHour.value : currentWeatherData.precipitationLast3Hours.value;

Steps to reproduce the issue:

Somehow get the weather.gov API to return an object (example follows) whose "properties" object does not contain a "precipitationLastHour" key...

currentWeatherData

{
    "@context": [
        "https://geojson.org/geojson-ld/geojson-context.jsonld",
        {
            "@version": "1.1",
            "wx": "https://api.weather.gov/ontology#",
            "s": "https://schema.org/",
            "geo": "http://www.opengis.net/ont/geosparql#",
            "unit": "http://codes.wmo.int/common/unit/",
            "@vocab": "https://api.weather.gov/ontology#",
            "geometry": {
                "@id": "s:GeoCoordinates",
                "@type": "geo:wktLiteral"
            },
            "city": "s:addressLocality",
            "state": "s:addressRegion",
            "distance": {
                "@id": "s:Distance",
                "@type": "s:QuantitativeValue"
            },
            "bearing": {
                "@type": "s:QuantitativeValue"
            },
            "value": {
                "@id": "s:value"
            },
            "unitCode": {
                "@id": "s:unitCode",
                "@type": "@id"
            },
            "forecastOffice": {
                "@type": "@id"
            },
            "forecastGridData": {
                "@type": "@id"
            },
            "publicZone": {
                "@type": "@id"
            },
            "county": {
                "@type": "@id"
            }
        }
    ],
    "id": "https://api.weather.gov/stations/KROC/observations/2025-08-07T02:40:00+00:00",
    "type": "Feature",
    "geometry": {
        "type": "Point",
        "coordinates": [
            -77.67,
            43.12
        ]
    },
    "properties": {
        "@id": "https://api.weather.gov/stations/KROC/observations/2025-08-07T02:40:00+00:00",
        "@type": "wx:ObservationStation",
        "elevation": {
            "unitCode": "wmoUnit:m",
            "value": 169
        },
        "station": "https://api.weather.gov/stations/KROC",
        "stationId": "KROC",
        "stationName": "Rochester, Greater Rochester International Airport",
        "timestamp": "2025-08-07T02:40:00+00:00",
        "rawMessage": "",
        "textDescription": "Clear",
        "icon": "https://api.weather.gov/icons/land/night/skc?size=medium",
        "presentWeather": [],
        "temperature": {
            "unitCode": "wmoUnit:degC",
            "value": 22,
            "qualityControl": "V"
        },
        "dewpoint": {
            "unitCode": "wmoUnit:degC",
            "value": 18,
            "qualityControl": "V"
        },
        "windDirection": {
            "unitCode": "wmoUnit:degree_(angle)",
            "value": 160,
            "qualityControl": "V"
        },
        "windSpeed": {
            "unitCode": "wmoUnit:km_h-1",
            "value": 7.416,
            "qualityControl": "V"
        },
        "windGust": {
            "unitCode": "wmoUnit:km_h-1",
            "value": null,
            "qualityControl": "Z"
        },
        "barometricPressure": {
            "unitCode": "wmoUnit:Pa",
            "value": 102743.03,
            "qualityControl": "V"
        },
        "seaLevelPressure": {
            "unitCode": "wmoUnit:Pa",
            "value": null,
            "qualityControl": "Z"
        },
        "visibility": {
            "unitCode": "wmoUnit:m",
            "value": 16093.44,
            "qualityControl": "C"
        },
        "maxTemperatureLast24Hours": {
            "unitCode": "wmoUnit:degC",
            "value": null
        },
        "minTemperatureLast24Hours": {
            "unitCode": "wmoUnit:degC",
            "value": null
        },
        "precipitationLast3Hours": {
            "unitCode": "wmoUnit:mm",
            "value": null,
            "qualityControl": "Z"
        },
        "relativeHumidity": {
            "unitCode": "wmoUnit:percent",
            "value": 78.062863996432,
            "qualityControl": "V"
        },
        "windChill": {
            "unitCode": "wmoUnit:degC",
            "value": null,
            "qualityControl": "V"
        },
        "heatIndex": {
            "unitCode": "wmoUnit:degC",
            "value": 22.293863671017778,
            "qualityControl": "V"
        },
        "cloudLayers": [
            {
                "base": {
                    "unitCode": "wmoUnit:m",
                    "value": 3810
                },
                "amount": "CLR"
            }
        ]
    }
}

What did you expect to happen?

In case of a missing key there should be some indication in the logs, or display an error on screen?

What actually happened?

Console indicated missing object error at line 221 of weathergov.js

Additional comments

No response

Participation

• I am willing to submit a pull request for this change.

[davidrea]

Just noticed age and version number on #3124 - looks like this remains an issue in 2.32.0.

It appears the ? chaining of the assignment was to try to deal with this situation, but if the precipitationLastHour child object simply isn't there, then referencing .value on it results in an error.

Looks like instead of:

currentWeather.precipitationAmount = currentWeatherData.precipitationLastHour.value ? currentWeatherData.precipitationLastHour.value : currentWeatherData.precipitationLast3Hours.value;

It should be:

currentWeather.precipitationAmount = currentWeatherData.precipitationLastHour ? currentWeatherData.precipitationLastHour.value : currentWeatherData.precipitationLast3Hours.value;

[davidrea]

A more thoroughly defensive approach could look like:

currentWeather.precipitationAmount = 
    (currentWeatherData.precipitationLastHour && currentWeatherData.precipitationLastHour.value) ? 
    currentWeatherData.precipitationLastHour.value : 
    (currentWeatherData.precipitationLast3Hours && currentWeatherData.precipitationLast3Hours.value) ?
    currentWeatherData.precipitationLast3Hours.value : null;

Elsewhere in the file there are some similar checks, but these appear to be more oriented toward situations when the API returns a JSON object with the correct properties present, but with the values actually set to null:

if (currentWeatherData.heatIndex.value !== null) {
	currentWeather.feelsLikeTemp = currentWeatherData.heatIndex.value;
} else if (currentWeatherData.windChill.value !== null) {
	currentWeather.feelsLikeTemp = currentWeatherData.windChill.value;
} else {
	currentWeather.feelsLikeTemp = currentWeatherData.temperature.value;
}

[rejas]

Thanks for your report @davidrea What do you think of my solution in the linked PR?

[richardkiene]

@rejas I manually edited my weathergov.js and can confirm that this fix works.

[davidrea]

Looks good to me!

[rejas]

Cool. Can @sdetweil @KristjanESPERANTO or @khassel take a look at the PR too?

[davidrea]

❤️❤️ open-source! Thanks @khassel @rejas!