From 3354d4ad3e2bfde5706649c2ca3725fa51a42477 Mon Sep 17 00:00:00 2001
From: dancode-188 <danbitengo@gmail.com>
Date: Sun, 28 Dec 2025 02:10:43 +0300
Subject: [PATCH] fix: normalize undefined to null and replace placeholders,
 fixes #14 #15

Two related issues in variable extraction:

1. extractVariables could return undefined when JSONPath finds nothing,
   but should return null for consistency with error handling.

2. interpolateVariables kept {{placeholder}} syntax when variables were
   undefined/null instead of replacing them with string representations.

Changes:
- Normalize JSONPath undefined results to null
- Replace undefined variables with 'undefined' string
- Replace null variables with 'null' string

This makes variable handling consistent and prevents stale placeholders
in interpolated text.
---
 src/lib/variable-extraction-service.ts | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/lib/variable-extraction-service.ts b/src/lib/variable-extraction-service.ts
index 75eafb4..14e37c6 100644
--- a/src/lib/variable-extraction-service.ts
+++ b/src/lib/variable-extraction-service.ts
@@ -40,7 +40,8 @@ class VariableExtractionService {
           wrap: false,
         });
 
-        extracted[extraction.name] = result;
+        // Normalize undefined to null for consistency
+        extracted[extraction.name] = result === undefined ? null : result;
       } catch (error) {
         console.error(`Failed to extract variable ${extraction.name}:`, error);
         extracted[extraction.name] = null;
@@ -78,10 +79,14 @@ class VariableExtractionService {
       
       // Support nested paths like {{user.id}}
       const value = this.getNestedValue(variables, trimmedName);
-      
-      if (value === undefined || value === null) {
+
+      if (value === undefined) {
         console.warn(`Variable ${trimmedName} not found`);
-        return match; // Keep original if not found
+        return 'undefined';
+      }
+
+      if (value === null) {
+        return 'null';
       }
 
       return String(value);