ObjectBuffer

What is this?

The ObjectBuffer library provides an easy and flexible way to buffer properties on an Javascript object.

What?

Here an example: say you receive the temperature of a CPU via a WebSocket:

{
	'temperature': 33
}

And now you want to buffer the temperature to display a chart, with minimal changes in existing code. Instead of manually buffering / handling the property you can use ObjectBuffer to get the job done:

1.) Create an ObjectBuffer instance

	let ObjectBufferInstance = new ObjectBuffer;

2.) Adjust the server response

{
	'^temperature[5]': 33
}

3.) Put it through the ObjectBuffer

packet = ObjectBufferInstance.update(packet)

packet will now be:

{
	'temperature': [33, 0, 0, 0, 0] // <- yay, buffered data!
}

done!

Installation

$ npm install object-buffer --save

Property naming

ObjectBuffer only considers properties prefixed with a ^.

The structure is as follows: ^{propName}[{size}]@{dataIDPropName}<handler>

^{propName}[{size}]#{dataIDValue}<handler>

• propName – the property name to be created.
• size - size of the buffer.
• optional: dataIDPropName - property name of the data id.
• optional: dataIDValue - value of the data id.
• optional: handler - custom handler function.

Data ID value

The data ID value is needed when you want to flush the contents of a buffer. The ObjectBuffer library will clear the buffer as soon as the dataID value has changed.

Example

{'^temp[3]#1': 1} // {'temp': [1, 0, 0]} ; dataID value is 1
{'^temp[3]#1': 2} // {'temp': [2, 1, 0]} ; dataID value is 1
{'^temp[3]#1': 3} // {'temp': [3, 2, 1]} ; dataID value is 1
{'^temp[3]#2': 9} // {'temp': [9, 0, 0]} ; dataID value is 2 -> buffer cleared

It is also possible to use the value of another property:

{'^temp[3]@id': 1, 'id': 1} // {'temp': [1, 0, 0]} ; dataID value is 1
{'^temp[3]@id': 2, 'id': 1} // {'temp': [2, 1, 0]} ; dataID value is 1
{'^temp[3]@id': 3, 'id': 1} // {'temp': [3, 2, 1]} ; dataID value is 1
{'^temp[3]@id': 9, 'id': 2} // {'temp': [9, 0, 0]} ; dataID value is 2 -> buffer cleared

Handler function

It is also possible to define a custom handler which will be invoked every time the buffered property is updated:

Example

{
	'^temp[3]#id<handleTemp>': 1
}

let ObjectBufferInstance = new ObjectBuffer({
	handleTemp(requestedSize, suggestedInitialValue) {
		let instance = new ObjectBuffer.RingBuffer(requestedSize, suggestedInitialValue)

		this.update = (value) => {
			return instance.push(value).getAsArray()
		}
	}
})