feat(ipub): make #ensureID private and remove old code

.epub/example/OEBPS/scripts/ipub.js

@@ -4,35 +4,20 @@ class IPUBElement extends HTMLElement {
   static observedAttributes = ["id"];
 
   connectedCallback() {
-    this.ensureID();
+    this.#ensureID();
   }
 
   attributeChangedCallback(_name, _oldValue, _newValue) {
-    this.ensureID();
+    this.#ensureID();
   }
 
-  ensureID() {
-    if (this.id) {
-      return;
+  /**
+   * @private
+   */
+  #ensureID() {
+    if (!this.id) {
+      this.id = hashFromHTML(this);
     }
-
-    // INFO: Hash algorithm by Joe Freeman & Cristian Sanchez at StackOverflow:
-    // https://stackoverflow.com/a/16348977
-    // https://stackoverflow.com/a/3426956
-    //
-    // Licensed under CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0/)
-
-    let hash = 0;
-    this.innerHTML.split("").forEach((char) => {
-      hash = char.charCodeAt(0) + ((hash << 5) - hash);
-    });
-
-    let id = "";
-    for (let i = 0; i < 3; i++) {
-      id += ((hash >> (i * 8)) & 0xff).toString(16).padStart(2, "0");
-    }
-
-    this.id = id;
   }
 }
 
@@ -200,43 +185,41 @@ globalThis.addEventListener("load", () => {
     });
   });
 
-  for (const element of document.querySelectorAll(
-    `[data-ipub-trigger="on-screen"]`,
-  )) {
-    observer.observe(element);
-  }
 
-  document.addEventListener("scroll", async () => {
-    for (const [id, element] of onScreenMap) {
-      const perc = getPercentageInView(element);
-      // console.debug(`Element #${id} is now ${perc}% on screen`);
 
-      const played = element.getAttribute("data-ipub-trigger-played") == "true";
 
-      if (perc >= 100 && !played) {
-        await playIpubElement(element);
-        element.setAttribute("data-ipub-trigger-played", "true");
-      }
     }
-  });
-});
 
 /**
- * @param {Element} element
  */
-async function playIpubElement(element) {
-  switch (element.tagName) {
-    case "audio": {
-      /** @type {HTMLAudioElement} */
-      const audio = element;
 
-      // await audio.play();
-
-      break;
-    }
-    default:
-      break;
+/**
+ * @param {Readonly<Element>} el
+ * @param {number} [length=6]
+ * @returns {string}
+ *
+ * @copyright This function contains code from a hash algorithm by
+ * {@link https://stackoverflow.com/a/16348977|Joe Freeman} and
+ * {@link https://stackoverflow.com/a/3426956|Cristian Sanchez} at
+ * StackOverflow, licensed under {@link https://creativecommons.org/licenses/by-sa/3.0/|CC BY-SA 3.0}.
+ */
+function hashFromHTML(el, length = 6) {
+  const hexLength = length / 2;
+  if (hexLength % 2 !== 0) {
+    hexLength + 1;
   }
+
+  let hash = 0;
+  for (const char of el.innerHTML) {
+    hash = char.charCodeAt(0) + ((hash << 5) - hash);
+  }
+
+  let hex = "";
+  for (let i = 0; i < hexLength; i++) {
+    hex += ((hash >> (i * 8)) & 0xff).toString(16).padStart(2, "0");
+  }
+
+  return hex.substring(0, length);
 }
 
 /**