MagicMirrorOrg/MagicMirror · error · Error

setCallbacks() must be called before initialize()

Error message

setCallbacks() must be called before initialize()

What it means

openweathermap's initialize() requires callbacks to be registered first via setCallbacks(); it throws synchronously if onErrorCallback is not a function. This ensures the provider always has a channel to report later async failures (API key problems, fetch errors) instead of crashing unhandled.

Source

Thrown at defaultmodules/weather/providers/openweathermap.js:34

			location: false,
			lat: 0,
			lon: 0,
			apiKey: "",
			type: "current",
			updateInterval: 10 * 60 * 1000,
			...config
		};

		this.fetcher = null;
		this.onDataCallback = null;
		this.onErrorCallback = null;
		this.locationName = null;
	}

	initialize () {
		// Validate callbacks exist
		if (typeof this.onErrorCallback !== "function") {
			throw new Error("setCallbacks() must be called before initialize()");
		}

		if (!this.config.apiKey) {
			Log.error("[openweathermap] API key is required");
			this.onErrorCallback({
				message: "API key is required",
				translationKey: "MODULE_ERROR_UNSPECIFIED"
			});
			return;
		}

		this.#initializeFetcher();
	}

	setCallbacks (onData, onError) {
		this.onDataCallback = onData;
		this.onErrorCallback = onError;
	}

View on GitHub (pinned to 4b4a59534f)

Solutions

1. Call provider.setCallbacks(onDataCallback, onErrorCallback) before initialize()
2. Ensure both callbacks are functions (not undefined/null)
3. Reorder your bootstrap code so callback registration precedes initialize()

Example fix

// before
provider.initialize(config);
provider.setCallbacks(onData, onError);
// after
provider.setCallbacks(onData, onError);
provider.initialize(config);

if (typeof provider.onErrorCallback !== "function") {
  throw new Error("Call setCallbacks(onData, onError) before initialize()");
}
provider.initialize(config);

const isCallbackFn = (f) => typeof f === "function";

try {
  provider.initialize(config);
} catch (err) {
  if (err.message.includes("setCallbacks() must be called before initialize()")) {
    provider.setCallbacks(onData, onError);
    provider.initialize(config); // retry once with correct order
  } else throw err;
}

When it happens

Trigger: Calling initialize() before setCallbacks(), or calling setCallbacks() with missing/incorrect arguments so onErrorCallback stays undefined.

Common situations: Refactored init order after upgrade; forgetting the callbacks step in new wiring; passing setCallbacks(onData) with only one argument.

Related errors

• Unknown weather type: ${this.config.type}
• Unknown weather endpoint: ${this.config.weatherEndpoint}
• Latitude and longitude are required
• Unknown weather type: ${this.config.type}
• siteCode and provCode are required

AI-assisted analysis of MagicMirrorOrg/MagicMirror@4b4a59534f (2026-08-31). Data as JSON: /api/errors/856885b404b0d2f4. Report an issue: GitHub.