sflow/src/riffles.ts

sflow is a powerful and highly-extensible library designed for processing and manipulating streams of data effortlessly. Inspired by the functional programming paradigm, it provides a rich set of utilities for transforming streams, including chunking, fil

export function riffles<T>(sep: T): TransformStream<T, T> {
  let last: T;
  return new TransformStream({
    transform: (chunk, ctrl) => {
      if (undefined !== last) {
        ctrl.enqueue(last);
        ctrl.enqueue(sep);
      }
      last = chunk;
    },
    flush: (ctrl) => ctrl.enqueue(last),
  });
}