Deserialise spoilers back into slash command form (#11805)

* Deserialise spoilers back into slash command form

Fixes: element-hq/element-web#26344

* Appease the linter

Author: Johennes

src/editor/deserialize.ts

@@ -247,6 +247,10 @@ function parseNode(n: Node, pc: PartCreator, opts: IParseOptions, mkListItem?: (
 
                         return pc.plainWithEmoji(`${delimLeft}${tex}${delimRight}`);
                     }
+                    // Spoilers are translated back into their slash command form
+                    else if ((n as Element).hasAttribute("data-mx-spoiler")) {
+                        return [pc.plain("/spoiler "), ...parseChildren(n, pc, opts)];
+                    }
             }
     }
 

test/editor/deserialize-test.ts

@@ -98,6 +98,11 @@ describe("editor/deserialize", function () {
             expect(parts.length).toBe(1);
             expect(parts[0]).toStrictEqual({ type: "plain", text: "/me says DON'T SHOUT!" });
         });
+        it("spoiler", function () {
+            const parts = normalize(parseEvent(textMessage("/spoiler broiler"), createPartCreator()));
+            expect(parts.length).toBe(1);
+            expect(parts[0]).toStrictEqual({ type: "plain", text: "/spoiler broiler" });
+        });
     });
     describe("html messages", function () {
         it("inline styling", function () {
@@ -295,6 +300,13 @@ describe("editor/deserialize", function () {
             expect(parts.length).toBe(1);
             expect(parts[0]).toStrictEqual({ type: "plain", text: "/me says _DON'T SHOUT_!" });
         });
+        it("spoiler", function () {
+            const parts = normalize(
+                parseEvent(htmlMessage("<span data-mx-spoiler>broiler</span>"), createPartCreator()),
+            );
+            expect(parts.length).toBe(1);
+            expect(parts[0]).toStrictEqual({ type: "plain", text: "/spoiler broiler" });
+        });
         it("preserves nested quotes", () => {
             const html = "<blockquote>foo<blockquote>bar</blockquote></blockquote>";
             const parts = normalize(parseEvent(htmlMessage(html), createPartCreator()));