diff --git a/package.json b/package.json
index 4899803..32c40ca 100644
--- a/package.json
+++ b/package.json
@@ -56,10 +56,10 @@
   },
   "devDependencies": {
     "@babel/eslint-parser": "7.28.0",
-    "@types/node": "24.0.10",
+    "@types/node": "24.1.0",
     "@vitest/coverage-v8": "3.2.4",
-    "eslint": "9.30.1",
-    "eslint-plugin-jsdoc": "51.3.3",
+    "eslint": "9.32.0",
+    "eslint-plugin-jsdoc": "52.0.0",
     "typescript": "5.8.3",
     "vitest": "3.2.4"
   }
diff --git a/src/unconvert.js b/src/unconvert.js
index 5b2c90c..730e49a 100644
--- a/src/unconvert.js
+++ b/src/unconvert.js
@@ -30,7 +30,7 @@ export function unconvert(element, values) {
   if (ctype === 'JSON') {
     if (!Array.isArray(values)) throw new Error('JSON must be an array')
     const encoder = new TextEncoder()
-    return values.map(v => encoder.encode(JSON.stringify(v)))
+    return values.map(v => v === undefined ? undefined : encoder.encode(JSON.stringify(v)))
   }
   if (ctype === 'UTF8') {
     if (!Array.isArray(values)) throw new Error('strings must be an array')
diff --git a/test/unconvert.test.js b/test/unconvert.test.js
index 4f28595..57db79a 100644
--- a/test/unconvert.test.js
+++ b/test/unconvert.test.js
@@ -28,6 +28,20 @@ describe('unconvert', () => {
     expect(new TextDecoder().decode(result[1])).toEqual(JSON.stringify({ hello: 'world' }))
   })
 
+  it('should handle undefined values in JSON arrays', () => {
+    /** @type {SchemaElement} */
+    const schema = { name: 'test', converted_type: 'JSON' }
+    const input = [{ foo: 'bar' }, undefined, { hello: 'world' }]
+    const result = unconvert(schema, input)
+
+    expect(result).toHaveLength(3)
+    expect(result[0]).toBeInstanceOf(Uint8Array)
+    expect(result[1]).toBeUndefined()
+    expect(result[2]).toBeInstanceOf(Uint8Array)
+    expect(new TextDecoder().decode(result[0])).toEqual(JSON.stringify({ foo: 'bar' }))
+    expect(new TextDecoder().decode(result[2])).toEqual(JSON.stringify({ hello: 'world' }))
+  })
+
   it('should convert string array to Uint8Array when converted_type = UTF8', () => {
     /** @type {SchemaElement} */
     const schema = { name: 'test', converted_type: 'UTF8' }