Selecting specific value in an array using var

[opwierde]

A bit of a beginners question but I am new to JS and Node-RED.

I am reading values directly from my solar inverter web interface and am struggling with the kWh value. I have the data from the inverter in an array that lists the values in the order of days of the month. This is what I put in a function block (global.today contains the day of the month):

I want to select the correct value using var today: payload: msg.payload[today]
That does not work. If I test by sticking a number in, [27] for example, it does work.
Is there a solution for this?

[Steve-Mcl]

Impossible to tell unless you show us what is in global.today (my guess is it's empty or not between 0 & 29) also, expand the debug payload so we can see what's in it.

@opwierde

If I test by sticking a number in, [27] for example, it does work.
Is there a solution for this

Like I said above

Try putting node.warn("today = " + today) below var today then look in the debug sidebar - tell us what value you get

Regarding arrays...
you should always check that the index (today) is actually a number and that is >= 0 and < the array length (msg.payload.length) BEFORE trying to access an element of an array.

Ps, look at the side bar "context" to see what is in global.today.

[opwierde]

Thanks for the quick reply!

"today" looks like a number in the context screen, but not in the node.warn line

The array:
["9.638","8.927","11.47","19.44","19.22","18.93","19.67","19.11","18.53","19.92","19.93","18.86","16.56","17.19","21.32","20.01","22.43","22.25","22.49","22.61","22.62","22.33","21.89","22.17","21.91","18.94","22.49","0.000","0.000","0.000"]

[knolleary]

To access today you need to use global.get("today") not global.today

[opwierde]

Thanks! Works like a charm.