Use <details> element for collapsibles (#690)

* Remove unnecessary call to 'collapseSection'

The call is unnecessary since there is no corresponding toggle for hiding the
section of orphan instances.

* Use <details> for collapsibles

This makes them work even when JS is disabled. Closes #560.

4 files changed, 140 insertions, 70 deletions

diff --git a/haddock-api/resources/html/js-src/cookies.ts b/haddock-api/resources/html/js-src/cookies.ts
new file mode 100644
index 00000000..3b68d6d8
--- /dev/null
+++ b/haddock-api/resources/html/js-src/cookies.ts
@@ -0,0 +1,20 @@
+export function setCookie(name: string, value: string) {
+  document.cookie = name + "=" + encodeURIComponent(value) + ";path=/;";
+}
+
+export function clearCookie(name: string) {
+  document.cookie = name + "=;path=/;expires=Thu, 01-Jan-1970 00:00:01 GMT;";
+}
+
+export function getCookie(name: string) {
+  const nameEQ = name + "=";
+  const ca = document.cookie.split(';');
+  for (let i = 0; i < ca.length; i++) {
+    let c = ca[i];
+    while (c.charAt(0)==' ') c = c.substring(1,c.length);
+    if (c.indexOf(nameEQ) == 0) {
+      return decodeURIComponent(c.substring(nameEQ.length,c.length));
+    }
+  }
+  return null;
+}
\ No newline at end of file
diff --git a/haddock-api/resources/html/js-src/details-helper.ts b/haddock-api/resources/html/js-src/details-helper.ts
new file mode 100644
index 00000000..f13ac905
--- /dev/null
+++ b/haddock-api/resources/html/js-src/details-helper.ts
@@ -0,0 +1,106 @@
+import {getCookie} from "./cookies";
+
+interface HTMLDetailsElement extends HTMLElement {
+  open: boolean
+}
+
+interface DetailsInfo {
+  element: HTMLDetailsElement
+  openByDefault: boolean
+  toggles: HTMLElement[]
+}
+
+// Global state
+const detailsRegistry: { [id: string]: DetailsInfo } = {};
+const toggled: { [id: string]: true } = {}; /* stores which <details> are not in their default state */
+
+function lookupDetailsRegistry(id: string): DetailsInfo {
+  const info = detailsRegistry[id];
+  if (info == undefined) { throw new Error(`could not find <details> element with id '${id}'`); }
+  return info;
+}
+
+function onDetailsToggle(ev: Event) {
+  const element = ev.target as HTMLDetailsElement;
+  const id = element.id;
+  const info = lookupDetailsRegistry(id);
+  const isOpen = info.element.open;
+  for (const toggle of info.toggles) {
+    if (toggle.classList.contains('details-toggle-control')) {
+      toggle.classList.add(isOpen ? 'collapser' : 'expander');
+      toggle.classList.remove(isOpen ? 'expander' : 'collapser');
+    }
+  }
+  if (element.open == info.openByDefault) {
+    delete toggled[id];
+  } else {
+    toggled[id] = true;
+  }
+  rememberToggled();
+}
+
+function gatherDetailsElements() {
+  const els: HTMLDetailsElement[] = Array.prototype.slice.call(document.getElementsByTagName('details'));
+  for (const el of els) {
+    if (typeof el.id == "string" && el.id.length > 0) {
+      detailsRegistry[el.id] = {
+        element: el,
+        openByDefault: !!el.open,
+        toggles: [] // added later
+      };
+      el.addEventListener('toggle', onDetailsToggle);
+    }
+  }
+}
+
+function toggleDetails(id: string) {
+  const {element} = lookupDetailsRegistry(id);
+  element.open = !element.open;
+}
+
+function rememberToggled() {
+  const sections: string[] = Object.keys(toggled);
+  // cookie specific to this page; don't use setCookie which sets path=/
+  document.cookie = "toggled=" + encodeURIComponent(sections.join('+'));
+}
+
+function restoreToggled() {
+  const cookie = getCookie("toggled");
+  if (!cookie) { return; }
+  const ids = cookie.split('+');
+  for (const id of ids) {
+    const info = detailsRegistry[id];
+    toggled[id] = true;
+    if (info) {
+      info.element.open = !info.element.open;
+    }
+  }
+}
+
+function onToggleClick(ev: MouseEvent) {
+  ev.preventDefault();
+  const toggle = ev.currentTarget as HTMLElement;
+  const id = toggle.getAttribute('data-details-id');
+  if (!id) { throw new Error("element with class 'details-toggle' has no 'data-details-id' attribute!"); }
+  toggleDetails(id);
+}
+
+function initCollapseToggles() {
+  const toggles: HTMLElement[] = Array.prototype.slice.call(document.getElementsByClassName('details-toggle'));
+  toggles.forEach(toggle => {
+    const id = toggle.getAttribute('data-details-id');
+    if (!id) { throw new Error("element with class 'details-toggle' has no 'data-details-id' attribute!"); }
+    const info = lookupDetailsRegistry(id);
+    info.toggles.push(toggle);
+    toggle.addEventListener('click', onToggleClick);
+    if (toggle.classList.contains('details-toggle-control')) {
+      toggle.classList.add(info.element.open ? 'collapser' : 'expander');
+    }
+  });
+}
+
+export function init() {
+  gatherDetailsElements();
+  restoreToggled();
+  initCollapseToggles();
+}
\ No newline at end of file
diff --git a/haddock-api/resources/html/js-src/init.ts b/haddock-api/resources/html/js-src/init.ts
index 0619dfc3..877874ae 100644
--- a/haddock-api/resources/html/js-src/init.ts
+++ b/haddock-api/resources/html/js-src/init.ts
@@ -1,4 +1,5 @@
-import * as util from "./haddock-util";
+import * as styleMenu from "./style-menu";
+import * as detailsHelper from "./details-helper";
 import * as quickJump from "./quick-jump";
 
 function onDomReady(callback: () => void) {
@@ -14,8 +15,8 @@ function onDomReady(callback: () => void) {
 }
 
 onDomReady(() => {
-  util.addStyleMenu();
-  util.resetStyle();
-  util.restoreCollapsed();
+  document.body.classList.add('js-enabled');
+  styleMenu.init();
+  detailsHelper.init();
   quickJump.init();
 });
\ No newline at end of file
diff --git a/haddock-api/resources/html/js-src/haddock-util.ts b/haddock-api/resources/html/js-src/style-menu.ts
index 257ceb6a..3911655b 100644
--- a/haddock-api/resources/html/js-src/haddock-util.ts
+++ b/haddock-api/resources/html/js-src/style-menu.ts
@@ -1,5 +1,7 @@
 // Haddock JavaScript utilities
 
+import {getCookie, setCookie, clearCookie} from "./cookies";
+
 const rspace = /\s\s+/g,
     rtrim = /^\s+|\s+$/g;
 
@@ -37,7 +39,6 @@ function toggleClass(elem: Element, valueOn: string, valueOff: string, bool?: bo
   return bool;
 }
 
-
 function makeClassToggle(valueOn: string, valueOff: string): (elem: Element, bool?: boolean) => boolean {
   return function(elem, bool) {
     return toggleClass(elem, valueOn, valueOff, bool);
@@ -45,69 +46,6 @@ function makeClassToggle(valueOn: string, valueOff: string): (elem: Element, boo
 }
 
 const toggleShow = makeClassToggle("show", "hide");
-const toggleCollapser = makeClassToggle("collapser", "expander");
-
-function toggleSection(id: string): boolean {
-  const b = toggleShow(document.getElementById("section." + id) as Element);
-  toggleCollapser(document.getElementById("control." + id) as Element, b);
-  rememberCollapsed(id);
-  return b;
-}
-
-// TODO: get rid of global variables
-if (typeof window !== 'undefined') {
-  (window as any).toggleSection = toggleSection;
-}
-
-const collapsed: { [id: string]: boolean } = {};
-function rememberCollapsed(id: string) {
-  if(collapsed[id])
-    delete collapsed[id]
-  else
-    collapsed[id] = true;
-
-  const sections: string[] = [];
-  for(let i in collapsed) {
-    if(collapsed.hasOwnProperty(i))
-      sections.push(i);
-  }
-  // cookie specific to this page; don't use setCookie which sets path=/
-  document.cookie = "collapsed=" + encodeURIComponent(sections.join('+'));
-}
-
-export function restoreCollapsed() {
-  const cookie = getCookie("collapsed");
-  if(!cookie)
-    return;
-
-  const ids = cookie.split('+');
-  for(const i in ids)
-  {
-    if(document.getElementById("section." + ids[i]))
-      toggleSection(ids[i]);
-  }
-}
-
-function setCookie(name: string, value: string) {
-  document.cookie = name + "=" + encodeURIComponent(value) + ";path=/;";
-}
-
-function clearCookie(name: string) {
-  document.cookie = name + "=;path=/;expires=Thu, 01-Jan-1970 00:00:01 GMT;";
-}
-
-function getCookie(name: string) {
-  const nameEQ = name + "=";
-  const ca = document.cookie.split(';');
-  for (let i = 0; i < ca.length; i++) {
-    let c = ca[i];
-    while (c.charAt(0)==' ') c = c.substring(1,c.length);
-    if (c.indexOf(nameEQ) == 0) {
-      return decodeURIComponent(c.substring(nameEQ.length,c.length));
-    }
-  }
-  return null;
-}
 
 function addMenuItem(html: string) {
   const menu = document.getElementById("page-menu");
@@ -123,7 +61,7 @@ function styles(): HTMLLinkElement[] {
   return es.filter((a: HTMLLinkElement) => a.rel.indexOf("style") != -1 && a.title);
 }
 
-export function addStyleMenu() {
+function addStyleMenu() {
   const as = styles();
   let btns = "";
   as.forEach((a) => {
@@ -162,7 +100,7 @@ function setActiveStyleSheet(title: string) {
   styleMenu(false);
 }
 
-export function resetStyle() {
+function resetStyle() {
   const s = getCookie("haddock-style");
   if (s) setActiveStyleSheet(s);
 }
@@ -170,4 +108,9 @@ export function resetStyle() {
 function styleMenu(show?: boolean) {
   const m = document.getElementById('style-menu');
   if (m) toggleShow(m, show);
+}
+
+export function init() {
+  addStyleMenu();
+  resetStyle();
 }
\ No newline at end of file