diff --git a/lib/datatypes.js b/lib/datatypes.js
index a95f781..11a34c4 100644
--- a/lib/datatypes.js
+++ b/lib/datatypes.js
@@ -160,7 +160,9 @@ function decodeBinArray(buf, decodeElem) {
 
 // FIXME: one dimension only
 function encodeTextArray(arr, encodeElem) {
-  return JSON.stringify(arr.map(encodeElem)).replace(/^\[(.*)]$/, '{$1}');
+  return JSON.stringify(arr, function (_, elem) {
+    return this == arr && elem != null ? encodeElem(elem) : elem;
+  }).replace(/^\[(.*)]$/, '{$1}');
 }
 
 // FIXME: one dimension only
diff --git a/test/test.js b/test/test.js
index 331750d..867bdaa 100644
--- a/test/test.js
+++ b/test/test.js
@@ -556,7 +556,7 @@ it('param explicit type', async () => {
         },
       }, {
         type: 'text[]',
-        value: ['1', '2', '3'],
+        value: ['1', '2', '3', null],
       }, {
         type: 'bytea[]',
         value: ['x', 'y', 'z'],
@@ -567,7 +567,7 @@ it('param explicit type', async () => {
     'integer', 1,
     'boolean', true,
     'jsonb', 'hello',
-    'text[]', '{1,2,3}',
+    'text[]', '{1,2,3,NULL}',
     'bytea[]', '{"\\\\x78","\\\\x79","\\\\x7a"}',
   ]);
 });