Changing BridgeBase Java handviewer to the js version

bbi.js

// For the documentation on the js handviewer, see http://www.bridgebase.com/tools/hvdoc.html

const convertParam = function(key, value) {
  switch (key) {
    case "north":
      return ["n", value.replace(/^!\*!North\*/, "")]
    case "east":
      return ["e", value.replace(/^!\*!East\*/, "")]
    case "west":
      return ["w", value.replace(/^!\*!West\*/, "")]
    case "south":
      let v = value.replace(/^!\*!South\*/, "")
      // fixing the typo in 2ov1a.html
      if (v[0] !== 's' && v[0] !== 'S') v = 's' + v.substr(1)
      return ["s", v]
    case "dealer":
      return ["d", value[0]]
    case "bidding":
      return ["a", value]
    case "bblue":
    case "bred":
    case "bgreen":
      return null
    default:
      console.log("Encountered unknown key", key, value)
      return null
  }
}

const convertHandViewer = function(a) {
  const queryString = Array.from(a.childNodes)
    .filter(n => n.tagName === "PARAM")
    .map(n => convertParam(n.getAttribute("name"), n.getAttribute("value")))
    .filter(kv => kv !== null)
    .map(([k, v]) => k + '=' + v)
    .join('&')

  const iframe = document.createElement("iframe")
  iframe.setAttribute("src", "https://www.bridgebase.com/tools/handviewer.html?" + queryString)
  iframe.setAttribute("width", a.getAttribute("width"))
  iframe.setAttribute("height", a.getAttribute("height"))

  return iframe
}

const handViewerApplets = Array.from(document.getElementsByTagName("applet"))
  .filter(a => a.attributes["code"].value === "dealdoc.class")

handViewerApplets.forEach(function(a) {
  const iframeViewer = convertHandViewer(a)
  a.parentElement.replaceChild(iframeViewer, a)
})

Improving 2/1 Game Force is a great series of articles on bridge bidding. Unfortunately the website uses Java applets, a deprecated technology, to display the hands and sequences, making viewing very difficult. This snippet converts the data in the applet nodes to create iframes of the new js viewer.