Batch Sampling Example from my talk, Real-time Insights, powered by Reactive Programming

batchsampling.js

let buffer = getWebSocket()
  .bufferTime(1000);

let gate = new BehaviorSubject(true);
let batchSize = 50;
let batchSizeCounter = 0;

let results = gate
  .switchMap(enabled => enabled ? buffer : Observable.never())
  .do(buffer => {
    batchSizeCounter += buffer.length;

    if (batchSizeCounter >= batchSize) {
      // truncates the array, if it's over batchSize
      let overage = batchSizeCounter - batchSize;
      buffer.length = buffer.length - overage;
      // turns on the gate, pausing the stream
      gate.next(false);
      batchSizeCounter = 0;
    }
  });