How to store data in JSON file in Node-RED

[drmibell]

@zenofmud

you could use a JSONata expression

Or in JavaScript:

msg.payload.filter(function(item){return item.fitting === 'wall'}).length;
or
msg.payload.filter(function(item){return item.zone === 'bedroom1'}).length;

Not as neat as @zenofmud's expression but usable in a function node that might be doing a bunch of other stuff.