Even numbers only

by jib1

HTML

<script src="https://jan-ivar.github.io/dummy/progressbar.js"></script>
<div id="div"></div>

JavaScript

const console = {log: msg => div.innerHTML += `${msg}<br>`};

(async () => {
  try {
    const numbers = new ReadableStream({
      n: 0,
      pull(ctrl) { this.n <= 10 && ctrl.enqueue(this.n++); }
    });
  
    numbers
      .pipeThrough(new TransformStream({
        transform: (chunk, ctrl) => chunk % 2 || ctrl.enqueue(chunk)
      }))
      .pipeTo(new WritableStream({write: c => console.log(c)}));
  
  } catch (e) {
    console.log(`${e.name}: ${e.message}`);
  }
})();