copied from docsy 0.7.2

Author: titusfortner

website_and_docs/static/js/tabpane-persist.js

@@ -0,0 +1,116 @@
+// Storage key names and data attribute name:
+const td_persistStorageKeyNameBase = 'td-tp-persist';
+const td_persistCounterStorageKeyName = `${td_persistStorageKeyNameBase}-count`;
+const td_persistDataAttrName = `data-${td_persistStorageKeyNameBase}`;
+
+// Utilities
+
+const _tdPersistCssSelector = (attrValue) =>
+  attrValue
+    ? `[${td_persistDataAttrName}="${attrValue}"]`
+    : `[${td_persistDataAttrName}]`;
+
+const _tdStoragePersistKey = (tabKey) =>
+  td_persistStorageKeyNameBase + ':' + (tabKey || '');
+
+const _tdSupportsLocalStorage = () => typeof Storage !== 'undefined';
+
+// Helpers
+
+function tdPersistKey(key, value) {
+  // @requires: tdSupportsLocalStorage();
+
+  try {
+    if (value) {
+      localStorage.setItem(key, value);
+    } else {
+      localStorage.removeItem(key);
+    }
+  } catch (error) {
+    const action = value ? 'add' : 'remove';
+    console.error(
+      `Docsy tabpane: unable to ${action} localStorage key '${key}': `,
+      error
+    );
+  }
+}
+
+// Retrieve, increment, and store tab-select event count, then returns it.
+function tdGetTabSelectEventCountAndInc() {
+  // @requires: tdSupportsLocalStorage();
+
+  const storedCount = localStorage.getItem(td_persistCounterStorageKeyName);
+  let numTabSelectEvents = parseInt(storedCount) || 0;
+  numTabSelectEvents++;
+  tdPersistKey(td_persistCounterStorageKeyName, numTabSelectEvents.toString());
+  return numTabSelectEvents;
+}
+
+// Main functions
+
+function tdActivateTabsWithKey(key) {
+  if (!key) return;
+
+  document.querySelectorAll(_tdPersistCssSelector(key)).forEach((element) => {
+    new bootstrap.Tab(element).show();
+  });
+}
+
+function tdPersistActiveTab(activeTabKey) {
+  if (!_tdSupportsLocalStorage()) return;
+
+  tdPersistKey(
+    _tdStoragePersistKey(activeTabKey),
+    tdGetTabSelectEventCountAndInc()
+  );
+  tdActivateTabsWithKey(activeTabKey);
+}
+
+// Handlers
+
+function tdGetAndActivatePersistedTabs(tabs) {
+  // Get unique persistence keys of tabs in this page
+  var keyOfTabsInThisPage = [
+    ...new Set(
+      Array.from(tabs).map((el) => el.getAttribute(td_persistDataAttrName))
+    ),
+  ];
+
+  // Create a list of active tabs with their age:
+  let key_ageList = keyOfTabsInThisPage
+    // Map to [tab-key, last-activated-age]
+    .map((k) => [
+      k,
+      parseInt(localStorage.getItem(_tdStoragePersistKey(k))) || 0,
+    ])
+    // Exclude tabs that have never been activated
+    .filter(([k, v]) => v)
+    // Sort from oldest selected to most recently selected
+    .sort((a, b) => a[1] - b[1]);
+
+  // Activate tabs from the oldest to the newest
+  key_ageList.forEach(([key]) => {
+    tdActivateTabsWithKey(key);
+  });
+
+  return key_ageList;
+}
+
+function tdRegisterTabClickHandler(tabs) {
+  tabs.forEach((tab) => {
+    tab.addEventListener('click', () => {
+      const activeTabKey = tab.getAttribute(td_persistDataAttrName);
+      tdPersistActiveTab(activeTabKey);
+    });
+  });
+}
+
+// Register listeners and activate tabs
+
+window.addEventListener('DOMContentLoaded', () => {
+  if (!_tdSupportsLocalStorage()) return;
+
+  var allTabsInThisPage = document.querySelectorAll(_tdPersistCssSelector());
+  tdRegisterTabClickHandler(allTabsInThisPage);
+  tdGetAndActivatePersistedTabs(allTabsInThisPage);
+});