Debounce node for Node Red.

Debounce Node

// A little function to debounce messages 
// that tend to flip flop a lot

// Uses the message topic as the key.

var debounceTracker = global.get("debounceTracker");

if (!debounceTracker) {
    debounceTracker = {};
}

// Get the last value (payload) of the last
// message on this topic.
node.warn(debounceTracker);

var last = debounceTracker[msg.topic];

// If it's a new message, construct a 
// fake last instance of it.
if (!last) {
    last = {
        count: 0,
        payload: msg.payload
    }
}
node.warn(last);
// Record a match.
if (last.payload && last.payload == msg.payload) {
    last.count = last.count + 1;
} else {
    last.count = 1;
    last.payload = msg.payload;
}

debounceTracker[msg.topic] = last;

global.set("debounceTracker", debounceTracker);

node.status({text: last.count})

if (last.count == 5) {
    return msg;
}