adds element handler prop with new props arg

app/javascript/mastodon/components/emoji/html.tsx

@@ -4,6 +4,7 @@ import classNames from 'classnames';
 
 import type { CustomEmojiMapArg } from '@/mastodon/features/emoji/types';
 import { isModernEmojiEnabled } from '@/mastodon/utils/environment';
+import type { OnElementHandler } from '@/mastodon/utils/html';
 import { htmlStringToComponents } from '@/mastodon/utils/html';
 import { polymorphicForwardRef } from '@/types/polymorphic';
 
@@ -14,6 +15,7 @@ interface EmojiHTMLProps {
   htmlString: string;
   extraEmojis?: CustomEmojiMapArg;
   className?: string;
+  onElement?: OnElementHandler;
 }
 
 export const ModernEmojiHTML = polymorphicForwardRef<'div', EmojiHTMLProps>(
@@ -23,13 +25,15 @@ export const ModernEmojiHTML = polymorphicForwardRef<'div', EmojiHTMLProps>(
       htmlString,
       as: asProp = 'div', // Rename for syntax highlighting
       className = '',
+      onElement,
       ...props
     },
     ref,
   ) => {
     const contents = useMemo(
-      () => htmlStringToComponents(htmlString, { onText: textToEmojis }),
-      [htmlString],
+      () =>
+        htmlStringToComponents(htmlString, { onText: textToEmojis, onElement }),
+      [htmlString, onElement],
     );
 
     return (
@@ -46,6 +50,7 @@ export const ModernEmojiHTML = polymorphicForwardRef<'div', EmojiHTMLProps>(
     );
   },
 );
+ModernEmojiHTML.displayName = 'ModernEmojiHTML';
 
 export const LegacyEmojiHTML = polymorphicForwardRef<'div', EmojiHTMLProps>(
   (props, ref) => {
@@ -54,6 +59,7 @@ export const LegacyEmojiHTML = polymorphicForwardRef<'div', EmojiHTMLProps>(
       htmlString,
       extraEmojis,
       className,
+      onElement,
       ...rest
     } = props;
     const Wrapper = asElement ?? 'div';
@@ -67,6 +73,7 @@ export const LegacyEmojiHTML = polymorphicForwardRef<'div', EmojiHTMLProps>(
     );
   },
 );
+LegacyEmojiHTML.displayName = 'LegacyEmojiHTML';
 
 export const EmojiHTML = isModernEmojiEnabled()
   ? ModernEmojiHTML

app/javascript/mastodon/utils/__tests__/html-test.ts

@@ -53,13 +53,19 @@ describe('html', () => {
 
     it('calls onElement callback', () => {
       const input = '<p>lorem ipsum</p>';
-      const onElement = vi.fn(
-        (element: HTMLElement, children: React.ReactNode[]) =>
-          React.createElement(element.tagName.toLowerCase(), {}, ...children),
+      const onElement = vi.fn<html.OnElementHandler>(
+        (element, props, children) =>
+          React.createElement(
+            element.tagName.toLowerCase(),
+            props,
+            ...children,
+          ),
       );
       html.htmlStringToComponents(input, { onElement });
       expect(onElement).toHaveBeenCalledExactlyOnceWith(
         expect.objectContaining({ tagName: 'P' }),
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+        expect.objectContaining({ key: expect.any(String) }),
         expect.arrayContaining(['lorem ipsum']),
         {},
       );
@@ -71,6 +77,8 @@ describe('html', () => {
       const output = html.htmlStringToComponents(input, { onElement });
       expect(onElement).toHaveBeenCalledExactlyOnceWith(
         expect.objectContaining({ tagName: 'P' }),
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+        expect.objectContaining({ key: expect.any(String) }),
         expect.arrayContaining(['lorem ipsum']),
         {},
       );

app/javascript/mastodon/utils/html.ts

@@ -32,14 +32,21 @@ interface QueueItem {
   depth: number;
 }
 
-export interface HTMLToStringOptions<Arg extends Record<string, unknown>> {
+export type OnElementHandler<
+  Arg extends Record<string, unknown> = Record<string, unknown>,
+> = (
+  element: HTMLElement,
+  props: Record<string, unknown>,
+  children: React.ReactNode[],
+  extra: Arg,
+) => React.ReactNode;
+
+export interface HTMLToStringOptions<
+  Arg extends Record<string, unknown> = Record<string, unknown>,
+> {
   maxDepth?: number;
   onText?: (text: string, extra: Arg) => React.ReactNode;
-  onElement?: (
-    element: HTMLElement,
-    children: React.ReactNode[],
-    extra: Arg,
-  ) => React.ReactNode;
+  onElement?: OnElementHandler<Arg>;
   onAttribute?: (
     name: string,
     value: string,
@@ -125,9 +132,57 @@ export function htmlStringToComponents<Arg extends Record<string, unknown>>(
         const children: React.ReactNode[] = [];
         let element: React.ReactNode = undefined;
 
+        // Generate props from attributes.
+        const key = `html-${uniqueIdCounter++}`; // Get the current key and then increment it.
+        const props: Record<string, unknown> = { key };
+        for (const attr of node.attributes) {
+          let name = attr.name.toLowerCase();
+
+          // Custom attribute handler.
+          if (onAttribute) {
+            const result = onAttribute(
+              name,
+              attr.value,
+              node.tagName.toLowerCase(),
+              extraArgs,
+            );
+            if (result) {
+              const [cbName, value] = result;
+              props[cbName] = value;
+            }
+          } else {
+            // Check global attributes first, then tag-specific ones.
+            const globalAttr = globalAttributes[name];
+            const tagAttr = tagInfo.attributes?.[name];
+
+            // Exit if neither global nor tag-specific attribute is allowed.
+            if (!globalAttr && !tagAttr) {
+              continue;
+            }
+
+            // Rename if needed.
+            if (typeof tagAttr === 'string') {
+              name = tagAttr;
+            } else if (typeof globalAttr === 'string') {
+              name = globalAttr;
+            }
+
+            let value: string | boolean | number = attr.value;
+
+            // Handle boolean attributes.
+            if (value === 'true') {
+              value = true;
+            } else if (value === 'false') {
+              value = false;
+            }
+
+            props[name] = value;
+          }
+        }
+
         // If onElement is provided, use it to create the element.
         if (onElement) {
-          const component = onElement(node, children, extraArgs);
+          const component = onElement(node, props, children, extraArgs);
 
           // Check for undefined to allow returning null.
           if (component !== undefined) {
@@ -137,53 +192,6 @@ export function htmlStringToComponents<Arg extends Record<string, unknown>>(
 
         // If the element wasn't created, use the default conversion.
         if (element === undefined) {
-          const props: Record<string, unknown> = {};
-          props.key = `html-${uniqueIdCounter++}`; // Get the current key and then increment it.
-          for (const attr of node.attributes) {
-            let name = attr.name.toLowerCase();
-
-            // Custom attribute handler.
-            if (onAttribute) {
-              const result = onAttribute(
-                name,
-                attr.value,
-                node.tagName.toLowerCase(),
-                extraArgs,
-              );
-              if (result) {
-                const [cbName, value] = result;
-                props[cbName] = value;
-              }
-            } else {
-              // Check global attributes first, then tag-specific ones.
-              const globalAttr = globalAttributes[name];
-              const tagAttr = tagInfo.attributes?.[name];
-
-              // Exit if neither global nor tag-specific attribute is allowed.
-              if (!globalAttr && !tagAttr) {
-                continue;
-              }
-
-              // Rename if needed.
-              if (typeof tagAttr === 'string') {
-                name = tagAttr;
-              } else if (typeof globalAttr === 'string') {
-                name = globalAttr;
-              }
-
-              let value: string | boolean | number = attr.value;
-
-              // Handle boolean attributes.
-              if (value === 'true') {
-                value = true;
-              } else if (value === 'false') {
-                value = false;
-              }
-
-              props[name] = value;
-            }
-          }
-
           element = React.createElement(
             tagName,
             props,