Small fix

Author: matthewlipski

packages/core/src/editor/managers/ExtensionManager/extensions.ts

@@ -175,10 +175,13 @@ export function getDefaultExtensions(
     ShowSelectionExtension(options),
     SideMenuExtension(options),
     SuggestionMenu(options),
-    SyntaxHighlightingExtension(options.syntaxHighlighting),
     ...(options.trailingBlock !== false ? [TrailingNodeExtension()] : []),
   ] as ExtensionFactoryInstance[];
 
+  if (options.syntaxHighlighting) {
+    extensions.push(SyntaxHighlightingExtension(options.syntaxHighlighting));
+  }
+
   if (options.collaboration) {
     extensions.push(CollaborationExtension(options.collaboration));
   } else {

packages/core/src/extensions/SyntaxHighlighting/SyntaxHighlighting.test.ts

@@ -23,14 +23,16 @@ describe("SyntaxHighlightingExtension", () => {
     SyntaxHighlightingExtension(options)({ editor: fakeEditor() })
       .prosemirrorPlugins;
 
+  // Whether highlighting is enabled at all is decided by the editor (it only
+  // instantiates this extension when the `syntaxHighlighting` option is set), so
+  // the extension itself always installs the plugin once created.
   it("installs a highlight plugin when a highlighter is configured", () => {
     const plugins = pluginsFor({ createHighlighter: async () => ({}) as any });
 
     expect(plugins).toHaveLength(1);
   });
 
-  it("installs no plugin when no highlighter is configured", () => {
-    expect(pluginsFor(undefined)).toHaveLength(0);
-    expect(pluginsFor({})).toHaveLength(0);
+  it("installs the plugin even without a highlighter (it no-ops at parse time)", () => {
+    expect(pluginsFor({})).toHaveLength(1);
   });
 });

packages/core/src/extensions/SyntaxHighlighting/SyntaxHighlighting.ts

@@ -36,18 +36,11 @@ export const defaultHighlightBlock = (block: Block<any, any, any>) =>
  * blocks get highlighted (and as which language) is decided by the
  * `highlightBlock` option, so individual blocks don't configure it themselves.
  *
- * Highlighting is opt-in: the plugin is only installed when a `createHighlighter`
- * is configured.
+ * Highlighting is opt-in: this extension is only instantiated when the
+ * `syntaxHighlighting` option is configured (see `getDefaultExtensions`).
  */
 export const SyntaxHighlightingExtension = createExtension(
-  ({
-    editor,
-    options,
-  }: ExtensionOptions<SyntaxHighlightingOptions | undefined>) => {
-    if (!options?.createHighlighter) {
-      return { key: "syntaxHighlighting", prosemirrorPlugins: [] };
-    }
-
+  ({ editor, options }: ExtensionOptions<SyntaxHighlightingOptions>) => {
     const highlightBlock = options.highlightBlock ?? defaultHighlightBlock;
 
     // Every block with inline (text) content is a candidate; `highlightBlock`