Generically wrap a stream of data values as an thenble-like async iterator

modular-async-iterator_streamer.md

Find yourself with a callback you'd like to make its passed values iterable--ie useful in a for await loop?

function Streamer(key) {
  const _ = Object.create(null);
  _.key = key;
  _.resolver = null;
  _.dataQueue = [];
  const push = function (newData) {
    if (this.resolver) {
      this.resolver({ value: newData, done: false });
      this.resovler = null;
    } else {
      this.dataQueue.push(newData);
    }
  }.bind(_);
  const pull = function () {
    const self = this;
    return new Promise((r) => {
      if (self.dataQueue.length) {
        r({ value: self.dataQueue.shift(), done: false });
      } else {
        self.resolver = r;
      }
    });
  }.bind(_);
  return {
    push,
    pull,
    [Symbol.asyncIterator]() {
      return {
        next: this.pull,
      };
    },
  };
}

Now can be used to create Readable wrapped data sources so that the data ca... must flow.

Best way to handle error/rejection case? Note while there are many settled resolutions, should only need to be one rejection else restart.