diff --git a/src/api/ruleMapping/ruleMapping.service.spec.ts b/src/api/ruleMapping/ruleMapping.service.spec.ts
index d622b00..7a3b4cf 100644
--- a/src/api/ruleMapping/ruleMapping.service.spec.ts
+++ b/src/api/ruleMapping/ruleMapping.service.spec.ts
@@ -146,7 +146,7 @@ describe('RuleMappingService', () => {
           type: 'expressionNode',
           content: {
             expressions: [
-              { key: 'expr1', value: 'field3' },
+              { key: 'expr1', value: 'field3 > 5' },
               { key: 'expr2', value: 'complexExpr + 2' },
             ],
           },
@@ -157,7 +157,7 @@ describe('RuleMappingService', () => {
       const result = await service.extractFields(nodes, 'inputs');
       expect(result).toEqual({
         inputs: [
-          { key: 'expr1', property: 'field3', exception: null },
+          { key: 'expr1', property: 'expr1', exception: 'field3 > 5' },
           { key: 'expr2', property: 'expr2', exception: 'complexExpr + 2' },
         ],
       });
diff --git a/src/api/ruleMapping/ruleMapping.service.ts b/src/api/ruleMapping/ruleMapping.service.ts
index 4580027..15b9e16 100644
--- a/src/api/ruleMapping/ruleMapping.service.ts
+++ b/src/api/ruleMapping/ruleMapping.service.ts
@@ -64,11 +64,7 @@ export class RuleMappingService {
     const results = await Promise.all(promises);
     const fields = results.flat();
 
-    const uniqueFieldsMap = new Map<string, any>();
-
-    fields.forEach((field) => {
-      uniqueFieldsMap.set(field.property, field);
-    });
+    const uniqueFieldsMap = new Map(fields.map((field) => [field.property, field]));
 
     const uniqueFields = Array.from(uniqueFieldsMap.values());
     return { [fieldKey]: uniqueFields };