Filter attributes with node red

[Ascotg]

Hi there,

I'm trying to filter the attributes (prices for the next 48 hours) via Node-red but I get the following error:

TypeError: Cannot read properties of undefined (reading 'prices_today')

My function, to get the first price, looks like this:

msg.payload = msg.payload.attributes.prices_today[0].price; return msg;

And here's my Node-Red config:

[{"id":"aaf8249566ac4136","type":"inject","z":"6407955a01e5b2fa","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":260,"y":320,"wires":[["a39eda9e97a5cd11"]]},{"id":"a572c0de5d1094b4","type":"debug","z":"6407955a01e5b2fa","name":"debug 1","active":true,"tosidebar":true,"console":true,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":890,"y":320,"wires":[]},{"id":"a39eda9e97a5cd11","type":"ha-get-entities","z":"6407955a01e5b2fa","name":"","server":"9405c3fe.d0a6c","version":0,"rules":[{"property":"entity_id","logic":"starts_with","value":"sensor.epex_be_and_costs_average_electricity_price_today","valueType":"str"}],"output_type":"array","output_empty_results":false,"output_location_type":"msg","output_location":"payload","output_results_count":1,"x":470,"y":320,"wires":[["a6c18e37d3cb14aa"]]},{"id":"a6c18e37d3cb14aa","type":"function","z":"6407955a01e5b2fa","name":"function 1","func":"msg.payload = msg.payload.attributes.prices_today[0].price;;\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":680,"y":320,"wires":[["a572c0de5d1094b4"]]},{"id":"9405c3fe.d0a6c","type":"server","name":"Home Assistant","addon":true}]

[Ascotg]

I found my own answer (in hindsight, I'm really a newbie to Node-Red):

When polling 'get entities' you get an object (what's in a name) where you can copy information out of by selecting the correct path.

In my case that was : msg.payload[0].attributes.prices[0].price

You can find more info on objects and paths to info in an object here:
https://nodered.org/docs/user-guide/messages

Here's my node red flow:

[{"id":"aaf8249566ac4136","type":"inject","z":"6407955a01e5b2fa","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":260,"y":320,"wires":[["a39eda9e97a5cd11"]]},{"id":"a572c0de5d1094b4","type":"debug","z":"6407955a01e5b2fa","name":"debug 1","active":true,"tosidebar":true,"console":true,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":890,"y":320,"wires":[]},{"id":"a39eda9e97a5cd11","type":"ha-get-entities","z":"6407955a01e5b2fa","name":"","server":"9405c3fe.d0a6c","version":0,"rules":[{"property":"entity_id","logic":"starts_with","value":"sensor.epex_be_and_costs_average_electricity_price_today","valueType":"str"}],"output_type":"array","output_empty_results":false,"output_location_type":"msg","output_location":"payload","output_results_count":1,"x":470,"y":320,"wires":[["a6c18e37d3cb14aa"]]},{"id":"a6c18e37d3cb14aa","type":"function","z":"6407955a01e5b2fa","name":"function 1","func":"msg.payload = msg.payload[0].attributes.prices[0].price;\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":680,"y":320,"wires":[["a572c0de5d1094b4"]]},{"id":"9405c3fe.d0a6c","type":"server","name":"Home Assistant","addon":true}]