fix(api-service): variable not removed from preview

apps/api/src/app/workflows-v2/usecases/generate-preview/generate-preview.usecase.ts

@@ -31,7 +31,7 @@ import { GeneratePreviewCommand } from './generate-preview.command';
 import { BuildPayloadSchemaCommand } from '../build-payload-schema/build-payload-schema.command';
 import { BuildPayloadSchema } from '../build-payload-schema/build-payload-schema.usecase';
 import { Variable } from '../../util/template-parser/liquid-parser';
-import { keysToObject } from '../../util/utils';
+import { keysToObject, mergeCommonObjectKeys } from '../../util/utils';
 import { isObjectTipTapNode } from '../../util/tip-tap.util';
 import { buildVariables } from '../../util/build-variables';
 
@@ -159,7 +159,13 @@ export class GeneratePreviewUsecase {
       finalVariablesExample = previewTemplateData.variablesExample;
     }
 
-    finalVariablesExample = _.merge(finalVariablesExample, commandVariablesExample || {});
+    if (commandVariablesExample && Object.keys(commandVariablesExample).length > 0) {
+      // merge only values of common keys between finalVariablesExample and commandVariablesExample
+      finalVariablesExample = mergeCommonObjectKeys(
+        commandVariablesExample as Record<string, unknown>,
+        finalVariablesExample as Record<string, unknown>
+      );
+    }
 
     return finalVariablesExample;
   }

apps/api/src/app/workflows-v2/util/utils.ts

@@ -5,7 +5,6 @@ import set from 'lodash/set';
 import values from 'lodash/values';
 import isObject from 'lodash/isObject';
 import isArray from 'lodash/isArray';
-
 import { BadRequestException } from '@nestjs/common';
 
 import { JSONSchemaDto } from '@novu/shared';
@@ -165,3 +164,37 @@ export function keysToObject(keys: string[], { fn } = { fn: (key: string) => key
 
   return result;
 }
+
+/**
+ * Merges common/overlapping object keys from source into target.
+ *
+ * @example
+ * Target: { subscriber: { phone: '{{subscriber.phone}}', name: '{{subscriber.name}}' } }
+ * Source: { subscriber: { phone: '123' }, payload: { someone: '{{payload.someone}}' }}
+ * Result: { subscriber: { phone: '123', name: '{{subscriber.name}}' } }
+ */
+export function mergeCommonObjectKeys(
+  source: Record<string, unknown>,
+  target: Record<string, unknown>
+): Record<string, unknown> {
+  /* eslint-disable no-param-reassign */
+  return Object.entries(target).reduce(
+    (merged, [key, targetValue]) => {
+      const sourceValue = source[key];
+
+      // If both source and target values are objects, recursively merge them
+      if (isObject(targetValue) && isObject(sourceValue)) {
+        merged[key] = mergeCommonObjectKeys(
+          sourceValue as Record<string, unknown>,
+          targetValue as Record<string, unknown>
+        );
+      } else {
+        // Otherwise, use the target value if it exists, otherwise use the source value
+        merged[key] = sourceValue ?? targetValue;
+      }
+
+      return merged;
+    },
+    {} as Record<string, unknown>
+  );
+}