fix(v2): ignore import declarations in excerpt (#2380)

* fix(v2): ignore import declarations in excerpt

* Update index.ts

Co-authored-by: Yangshun Tay <tay.yang.shun@gmail.com>

packages/docusaurus-utils/src/index.ts

@@ -182,6 +182,9 @@ export function getSubFolder(file: string, refDir: string): string | null {
   return match && match[1];
 }
 
+// Regex for an import statement.
+const importRegexString = '^(.*import){1}(.+){0,1}\\s[\'"](.+)[\'"];';
+
 export function parse(
   fileString: string,
 ): {
@@ -193,7 +196,18 @@ export function parse(
 } {
   const options: {} = {
     excerpt: (file: matter.GrayMatterFile<string>): void => {
-      file.excerpt = file.content.trim().split('\n', 1).shift();
+      let fileContent = file.content.trimLeft();
+      
+      // Hacky way of stripping out import statements from the excerpt
+      // TODO: Find a better way to do so, possibly by compiling the Markdown content, 
+      // stripping out HTML tags and obtaining the first line.
+      if (RegExp(importRegexString).test(fileContent)) {
+        fileContent = fileContent
+          .replace(RegExp(importRegexString, 'gm'), '')
+          .trimLeft();
+      }
+
+      file.excerpt = fileContent.split('\n', 1).shift();
     },
   };