Nodes suggestion for timed rolling average and desynchronised sum

General
41

Hi Colin,

your code is very useful. Thank you for this. Although it's working I get an error as follows:

Referring to the line below:

while (buffer[0] && buffer[0].timestamp < now - range)

it says:

The left-hand side of an arithmetic operation must be of type 'any', 'number', 'bigint' or an enum type.

How can I resolve this ?

Thank you...

42

Can you post the full code of the function you are using please?

43

Though probably you just need to change now to now.getTime()
The latest linter in node-red doesn't know about subtracting Date objects. The code will work as it is because the interpreter will call getTime() automatically.

44

I used your code from above (great btw) without any changes.

// determines the average of all payload values passed in 
// over the specified time range
const range = 20 * 60 * 1000;   // window time millisecs
let buffer = context.get('buffer') || [];
let total = context.get('total') || 0;   // the accumulated total so far

let now = new Date();
let value = Number(msg.payload);
// remove any samples that are too old
while (buffer[0] && buffer[0].timestamp < now - range) {
    // remove oldest sample from array and total
    node.warn(`removing oldest ${buffer[0].timestamp}`);
    total -= buffer[0].value;
    buffer.shift();
}
// add the new sample to the end
buffer.push({timestamp: now, value: value});
total += value;

context.set('buffer', buffer);
context.set('total', total);

msg.payload = total/buffer.length;
node.warn(`length: ${buffer.length}, total: ${total}, average: ${msg.payload}`);
return msg;
45

That was the solution!! Thank you so much!!

All the best....

46

One more short question do I have to adjust the declaration below also ? I.e. does 'let now...' should become 'let now.getTime()...' ?

47

Try it and see.