Added case for the extension

src/errors/specification-file.ts

@@ -24,7 +24,7 @@ export class SpecificationURLNotFound extends SpecificationFileError {
   }
 }
 
-type From = 'file' | 'url' | 'context'
+type From = 'file' | 'url' | 'context' | 'invalid file'
 
 export class ErrorLoadingSpec extends Error {
   private readonly errorMessages = {
@@ -35,15 +35,19 @@ export class ErrorLoadingSpec extends Error {
     if (from === 'file') {
       this.name = 'error loading AsyncAPI document from file';
       this.message = `${param} file does not exist.`;
-    }
-    if (from === 'url') {
-      this.name = 'error loading AsyncAPI document from url';
-      this.message = `Failed to download ${param}.`;
-    }
-    if (from === 'context') {
-      this.name = 'error loading AsyncAPI document from context';
-      this.message = `${param} context name does not exist.`;
-    }
+    } else
+      if (from === 'url') {
+        this.name = 'error loading AsyncAPI document from url';
+        this.message = `Failed to download ${param}.`;
+      } else
+        if (from === 'context') {
+          this.name = 'error loading AsyncAPI document from context';
+          this.message = `${param} context name does not exist.`;
+        } else
+          if (from === 'invalid file') {
+            this.name = 'Invalid AsyncAPI file type';
+            this.message = 'cli only supports yml ,yaml ,json extension';
+          }
 
     if (!from) {
       this.name = 'error locating AsyncAPI document';

src/models/SpecificationFile.ts

@@ -182,6 +182,14 @@ export async function isURL(urlpath: string): Promise<boolean> {
 
 export async function fileExists(name: string): Promise<boolean> {
   try {
+    const extension = name.split('.')[1];
+
+    const allowedExtenstion=['yml','yaml','json'];
+
+    if (!allowedExtenstion.includes(extension)) {
+      throw new ErrorLoadingSpec('invalid file',name);
+    }
+
     if ((await lstat(name)).isFile()) {
       return true;
     }