fix: array index mapping error handling

src/types.ts

@@ -282,6 +282,7 @@ export type FlatMappingPaths = {
   to?: string;
   input?: string;
   output?: string;
+  [key: string]: any;
 };
 
 export type FlatMappingAST = FlatMappingPaths & {

src/utils/converter.ts

@@ -58,7 +58,15 @@
       ? flatMapping.inputExpr
       : createObjectExpression();
   }
-  return currrentOutputPropAST.value.elements[filterIndex];
+  const objectExpr = currrentOutputPropAST.value.elements[filterIndex];
+  if (!isLastPart && objectExpr?.type !== SyntaxType.OBJECT_EXPR) {
+    throw new JsonTemplateMappingError(
+      'Invalid mapping: invalid array index mapping',
+      flatMapping.input as string,
+      flatMapping.output as string,
+    );
+  }
+  return objectExpr;
 }
 
 function isPathWithEmptyPartsAndObjectRoot(expr: Expression) {

test/scenarios/mappings/data.ts

@@ -187,6 +187,10 @@ export const data: Scenario[] = [
       ],
     },
   },
+  {
+    mappingsPath: 'invalid_array_index_mappings.json',
+    error: 'Invalid mapping',
+  },
   {
     description: 'Index mappings in last part',
     mappings: [

test/scenarios/mappings/invalid_array_index_mappings.json

@@ -0,0 +1,10 @@
+[
+  {
+    "from": "$.products[*].a",
+    "to": "$.items[*].a"
+  },
+  {
+    "from": "$.products[*].b",
+    "to": "$.items[0].b"
+  }
+]