[lexical-markdown] Feature: add ability to control finding the end of a node matched by TextMatchTransformer

packages/lexical-markdown/src/MarkdownImport.ts

@@ -383,7 +383,14 @@ function importTextMatchTransformers(
       }
 
       const startIndex = match.index || 0;
-      const endIndex = startIndex + match[0].length;
+      const endIndex = transformer.getEndIndex
+        ? transformer.getEndIndex(textNode, match)
+        : startIndex + match[0].length;
+
+      if (endIndex === false) {
+        continue;
+      }
+
       let replaceNode, newTextNode;
 
       if (startIndex === 0) {

packages/lexical-markdown/src/MarkdownTransformers.ts

@@ -174,6 +174,15 @@ export type TextMatchTransformer = Readonly<{
    * Determines how the matched markdown text should be transformed into a node during the markdown import process
    */
   replace?: (node: TextNode, match: RegExpMatchArray) => void;
+  /**
+   * For import operations, this function can be used to determine the end index of the match, after `importRegExp` has matched.
+   * Without this function, the end index will be determined by the length of the match from `importRegExp`. Manually determining the end index can be useful if
+   * the match from `importRegExp` is not the entire text content of the node. That way, `importRegExp` can be used to match only the start of the node, and `getEndIndex`
+   * can be used to match the end of the node.
+   *
+   * @returns The end index of the match, or false if the match was unsuccessful and a different transformer should be tried.
+   */
+  getEndIndex?: (node: TextNode, match: RegExpMatchArray) => number | false;
   /**
    * Single character that allows the transformer to trigger when typed in the editor. This does not affect markdown imports outside of the markdown shortcut plugin.
    * If the trigger is matched, the `regExp` will be used to match the text in the second step.