function to format data for chart to plot series of timestamp,value
The topic of interest in the "function slice and aggregate...." It solves the problem of plotting {timestamp, value} points, not just adding a new value.
It originates from polling a public api that exposes recorded IoT data. The data received contains the latest value for the inquired sensors, however since the data is timestamped, these should be respected in the plotting.
Notice: The context stores the obtained dataset and adds points if the timestamp is not previously seen. Some memory is wasted maintaining a lookup array that is not used for anything.
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