diff --git a/ui/analyse/src/ctrl.ts b/ui/analyse/src/ctrl.ts
index a9f2d4d415..f4f4d34c43 100644
--- a/ui/analyse/src/ctrl.ts
+++ b/ui/analyse/src/ctrl.ts
@@ -42,7 +42,7 @@ import { AnaMove, StudyCtrl } from './study/interfaces';
 import { StudyPracticeCtrl } from './study/practice/interfaces';
 import { valid as crazyValid } from './crazy/crazyCtrl';
 import { PromotionCtrl } from 'chess/promotion';
-import { WikiTheory } from './wiki';
+import wikiTheory, { WikiTheory } from './wiki';
 
 export default class AnalyseCtrl {
   data: AnalyseData;
@@ -124,7 +124,7 @@ export default class AnalyseCtrl {
     this.promotion = new PromotionCtrl(this.withCg, () => this.withCg(g => g.set(this.cgConfig)), this.redraw);
 
     if (this.data.forecast) this.forecast = makeForecast(this.data.forecast, this.data, redraw);
-    if (this.opts.wiki) this.wiki = new WikiTheory();
+    if (this.opts.wiki) this.wiki = wikiTheory();
 
     if (lichess.AnalyseNVUI) this.nvui = lichess.AnalyseNVUI(redraw) as NvuiPlugin;
 
@@ -214,7 +214,7 @@ export default class AnalyseCtrl {
     this.onMainline = this.tree.pathIsMainline(path);
     this.fenInput = undefined;
     this.pgnInput = undefined;
-    this.wiki?.update(this.nodeList);
+    if (this.wiki) this.wiki(this.nodeList);
   };
 
   flip = () => {
diff --git a/ui/analyse/src/wiki.ts b/ui/analyse/src/wiki.ts
index 49ef0c22bf..ed1ebc8094 100644
--- a/ui/analyse/src/wiki.ts
+++ b/ui/analyse/src/wiki.ts
@@ -1,25 +1,48 @@
 import debounce from 'common/debounce';
 
-export class WikiTheory {
-  update = debounce(
+export type WikiTheory = (nodes: Tree.Node[]) => void;
+
+export default function wikiTheory(): WikiTheory {
+  const cache = new Map<string, string>();
+  const show = (html: string) => $('.analyse__wiki').html(html);
+
+  const plyPrefix = (node: Tree.Node) => `${Math.floor((node.ply + 1) / 2)}${node.ply % 2 === 1 ? '._' : '...'}`;
+
+  const wikiBooksUrl = 'https://en.wikibooks.org';
+  const apiArgs = 'origin=*&action=query&prop=extracts&formatversion=2&format=json&exchars=1200';
+
+  const removeEmptyParagraph = (html: string) => html.replace(/<p>(<br \/>|\s)*<\/p>/g, '');
+
+  const removeTableHeader = (html: string) => html.replace('<h2><span id="Theory_table">Theory table</span></h2>', '');
+  const removeTableExpl = (html: string) =>
+    html.replace(/For explanation of theory tables see theory table and for notation see algebraic notation.?/, '');
+  const removeContributing = (html: string) =>
+    html.replace('When contributing to this Wikibook, please follow the Conventions for organization.', '');
+
+  const readMore = (title: string) =>
+    `<p><a target="_blank" href="${wikiBooksUrl}/wiki/${title}">Read more on WikiBooks</a></p>`;
+
+  const transform = (html: string, title: string) =>
+    removeEmptyParagraph(removeTableHeader(removeTableExpl(removeContributing(html)))) + readMore(title);
+
+  return debounce(
     async (nodes: Tree.Node[]) => {
-      const pathParts = nodes.slice(1).map(n => `${this.plyPrefix(n)}${n.san}`);
+      const pathParts = nodes.slice(1).map(n => `${plyPrefix(n)}${n.san}`);
       const path = pathParts.join('/');
-      if (!path) this.show('');
-      else if (this.cache.has(path)) this.show(this.cache.get(path)!);
+      if (!path) show('');
+      else if (cache.has(path)) show(cache.get(path)!);
       else if (
         Array.from({ length: pathParts.length }, (_, i) => -i - 1)
           .map(i => pathParts.slice(0, i).join('/'))
-          .some(sub => this.cache.has(sub) && !this.cache.get(sub)!.length)
+          .some(sub => cache.has(sub) && !cache.get(sub)!.length)
       )
-        this.show('');
+        show('');
       else {
         const title = `Chess_Opening_Theory/${path}`;
-        const url = `${wikiBooksUrl}/w/api.php?titles=${title}&${this.urlArgs}`;
-        const res = await fetch(url);
+        const res = await fetch(`${wikiBooksUrl}/w/api.php?titles=${title}&${apiArgs}`);
         const saveAndShow = (html: string) => {
-          this.cache.set(path, html);
-          this.show(html);
+          cache.set(path, html);
+          show(html);
         };
         if (res.ok) {
           const json = await res.json();
@@ -31,25 +54,4 @@ export class WikiTheory {
     500,
     true
   );
-  private cache = new Map<string, string>();
-  private urlArgs = 'origin=*&action=query&prop=extracts&formatversion=2&format=json&exchars=1200';
-  private plyPrefix = (node: Tree.Node) => `${Math.floor((node.ply + 1) / 2)}${node.ply % 2 === 1 ? '._' : '...'}`;
-  private el = $('.analyse__wiki');
-  private show = (html: string) => this.el.html(html);
 }
-
-const wikiBooksUrl = 'https://en.wikibooks.org';
-
-const transform = (html: string, title: string) =>
-  removeEmptyParagraph(removeTableHeader(removeTableExpl(removeContributing(html)))) + readMore(title);
-
-const removeEmptyParagraph = (html: string) => html.replace(/<p>(<br \/>|\s)*<\/p>/g, '');
-
-const removeTableHeader = (html: string) => html.replace('<h2><span id="Theory_table">Theory table</span></h2>', '');
-const removeTableExpl = (html: string) =>
-  html.replace(/For explanation of theory tables see theory table and for notation see algebraic notation.?/, '');
-const removeContributing = (html: string) =>
-  html.replace('When contributing to this Wikibook, please follow the Conventions for organization.', '');
-
-const readMore = (title: string) =>
-  `<p><a target="_blank" href="${wikiBooksUrl}/wiki/${title}">Read more on WikiBooks</a></p>`;