yea

https://yea-ddl.pages.dev
https://deno.land/x/yea
usage

<html>
  <body>
    <script type="module">
      import {
        amen,
        pick,
        seq,
      } from "https://deno-emit-proxy.deno.dev/x/yea@v0.2.0/mod.ts";

      document.querySelector("button").addEventListener("click", () =>
        amen((index) => {
          return {
            sliceIndex: index,
            length: seq([0.0, 1, 0.5, 1]),
            loop: {
              length: seq([1, 1 / 2, 1 / 3, 1 / 4]),
              prob: 1,
            },
            swap: {
              index: pick([
                Math.floor(Math.random() * 16),
                Math.abs(index + (Math.floor(Math.random() * 32) - 16)),
              ]),
              prob: 0.4,
            },
            hop: {
              index: Math.abs(index + (Math.floor(Math.random() * 32) - 16)),
              prob: 0.3,
            },
          };
        })
      );
    </script>
    <button>start</button>
  </body>
</html>