improve j5 node sandbox

[boneskull]

Howdy,

I found it would be convenient if I could easily store my board or other device objects within the flow variable available to all "function" node sandboxes. e.g.:

// this is a j5 node
const left = new five.Relay({pin: 11, type: 'NC'});

left.on();

const relays = flow.get('relays') || {};
relays.left = left;
flow.set('relays', relays);

node.send({
    payload: {
        relay: 'left'
    }
});

Later, a "function" node:

// this is a plain old function node
const relay = flow.get('relays').left;
const data = msg.payload.data = {};
const isOn = relay.isOn;
data[`${msg.payload.relay}_on`] = isOn;
if (isOn) {
    node.status({fill: 'green', shape: 'dot', text: 'on'});
} else {
    node.status({fill: 'red', shape: 'ring', text: 'off'});
}

return msg;

Caveats:

• this may break compatibility with certain versions of Node-Red, but I couldn't say for sure
• this may break backwards compatibility in general (I'd recommend a "major" bump here)
• the code was mainly copypasta from the core function node source in Node-Red.

[monteslu]

This looks great. Thanks @boneskull I'll give it a spin

[monteslu]

Works great. Thanks!

[monteslu]

updated deps for latest j5, and published version 0.5.0