diff --git a/js_headers.t b/js_headers.t
index adfe760..caa0e10 100644
--- a/js_headers.t
+++ b/js_headers.t
@@ -54,6 +54,14 @@
             js_content content_length;
         }
 
+        location /content_length_arr {
+            js_content content_length_arr;
+        }
+
+        location /content_length_keys {
+            js_content content_length_keys;
+        }
+
         location /content_type {
             charset windows-1251;
 
@@ -61,10 +69,21 @@
             js_content content_type;
         }
 
+        location /content_type_arr {
+            charset windows-1251;
+
+            default_type text/plain;
+            js_content content_type_arr;
+        }
+
         location /content_encoding {
             js_content content_encoding;
         }
 
+        location /content_encoding_arr {
+            js_content content_encoding_arr;
+        }
+
         location /headers_list {
             js_content headers_list;
         }
@@ -85,6 +104,18 @@
             js_content hdr_out;
         }
 
+        location /hdr_out_array {
+            js_content hdr_out_array;
+        }
+
+        location /hdr_out_set_cookie {
+            js_content hdr_out_set_cookie;
+        }
+
+        location /hdr_out_single {
+            js_content hdr_out_single;
+        }
+
         location /ihdr_out {
             js_content ihdr_out;
         }
@@ -112,6 +143,21 @@
         r.finish();
     }
 
+    function content_length_arr(r) {
+        r.headersOut['Content-Length'] = [5];
+        r.headersOut['Content-Length'] = [];
+        r.headersOut['Content-Length'] = [4,3];
+        r.sendHeader();
+        r.send('XXX');
+        r.finish();
+    }
+
+    function content_length_keys(r) {
+        r.headersOut['Content-Length'] = 3;
+        var in_keys = Object.keys(r.headersOut).some(v=>v=='Content-Length');
+        r.return(200, `B:\${in_keys}`);
+    }
+
     function content_type(r) {
         r.headersOut['Content-Type'] = 'text/xml';
         r.headersOut['Content-Type'] = '';
@@ -119,6 +165,14 @@
         delete r.headersOut['Content-Type'];
         r.headersOut['Content-Type'] = 'text/xml; charset=utf-8';
         r.headersOut['Content-Type'] = 'text/xml; charset="utf-8"';
+        var in_keys = Object.keys(r.headersOut).some(v=>v=='Content-Type');
+        r.return(200, `B:\${in_keys}`);
+    }
+
+    function content_type_arr(r) {
+        r.headersOut['Content-Type'] = ['text/html'];
+        r.headersOut['Content-Type'] = [];
+        r.headersOut['Content-Type'] = [ 'text/xml', 'text/html'];
         r.return(200);
     }
 
@@ -130,6 +184,13 @@
         r.return(200);
     }
 
+    function content_encoding_arr(r) {
+        r.headersOut['Content-Encoding'] = 'test';
+        r.headersOut['Content-Encoding'] = [];
+        r.headersOut['Content-Encoding'] = ['test', 'gzip'];
+        r.return(200);
+    }
+
     function headers_list(r) {
         for (var h in {a:1, b:2, c:3}) {
             r.headersOut[h] = h;
@@ -195,6 +256,35 @@
         r.finish();
     }
 
+    function hdr_out_array(r) {
+        if (!r.args.hidden) {
+            r.headersOut['Foo'] = [r.args.fOO];
+            r.headersOut['Foo'] = [];
+            r.headersOut['Foo'] = ['bar', r.args.fOO];
+        }
+
+        if (r.args.scalar_set) {
+            r.headersOut['Foo'] = 'xxx';
+        }
+
+        r.return(200, `B:\${njs.dump(r.headersOut.foo)}`);
+    }
+
+    function hdr_out_single(r) {
+        r.headersOut.ETag = ['a', 'b'];
+        r.return(200, `B:\${njs.dump(r.headersOut.etag)}`);
+    }
+
+    function hdr_out_set_cookie(r) {
+        r.headersOut['Set-Cookie'] = [];
+        r.headersOut['Set-Cookie'] = ['a', 'b'];
+        delete r.headersOut['Set-Cookie'];
+        r.headersOut['Set-Cookie'] = 'e';
+        r.headersOut['Set-Cookie'] = ['c', '', null, 'd', 'f'];
+
+        r.return(200, `B:\${njs.dump(r.headersOut['Set-Cookie'])}`);
+    }
+
     function ihdr_out(r) {
         r.status = 200;
         r.headersOut['a'] = r.args.a;
@@ -213,7 +303,7 @@
 
 EOF
 
-$t->try_run('no njs')->plan(18);
+$t->try_run('no njs')->plan(34);
 
 ###############################################################################
 
@@ -235,6 +325,44 @@
 unlike(http_get('/hdr_out?foo='), qr/Foo:/, 'r.headersOut no value');
 unlike(http_get('/hdr_out?foo'), qr/Foo:/, 'r.headersOut no value 2');
 
+TODO: {
+local $TODO = 'not yet'
+	unless http_get('/njs') =~ /^([.0-9]+)$/m && $1 ge '0.4.0';
+
+like(http_get('/content_length_keys'), qr/B:true/, 'Content-Length in keys');
+like(http_get('/content_length_arr'), qr/Content-Length: 3/,
+	'set Content-Length arr');
+
+like(http_get('/content_type'), qr/B:true/, 'Content-Type in keys');
+like(http_get('/content_type_arr'), qr/Content-Type: text\/html/,
+	'set Content-Type arr');
+like(http_get('/content_encoding_arr'), qr/Content-Encoding: gzip/,
+	'set Content-Encoding arr');
+
+like(http_get('/hdr_out_array?foo=12345'), qr/Foo: bar\r\nFoo: 12345/,
+	'r.headersOut arr');
+like(http_get('/hdr_out_array'), qr/Foo: bar/,
+	'r.headersOut arr last is empty');
+like(http_get('/hdr_out_array?foo=abc'), qr/B:bar,abc/,
+	'r.headersOut get');
+like(http_get('/hdr_out_array'), qr/B:bar/, 'r.headersOut get2');
+like(http_get('/hdr_out_array?hidden=1'), qr/B:undefined/,
+	'r.headersOut get3');
+like(http_get('/hdr_out_array?scalar_set=1'), qr/B:xxx/,
+	'r.headersOut scalar set');
+like(http_get('/hdr_out_single'), qr/ETag: a\r\nETag: b/,
+	'r.headersOut single');
+like(http_get('/hdr_out_single'), qr/B:a/,
+	'r.headersOut single get');
+like(http_get('/hdr_out_set_cookie'), qr/Set-Cookie: c\r\nSet-Cookie: d/,
+	'set_cookie');
+like(http_get('/hdr_out_set_cookie'), qr/B:\['c','d','f']/,
+	'set_cookie2');
+unlike(http_get('/hdr_out_set_cookie'), qr/Set-Cookie: [abe]/,
+	'set_cookie3');
+
+}
+
 like(http(
 	'GET /hdr_in HTTP/1.0' . CRLF
 	. 'Cookie: foo' . CRLF
@@ -250,7 +378,7 @@
 
 TODO: {
 local $TODO = 'not yet'
-               unless http_get('/njs') =~ /^([.0-9]+)$/m && $1 ge '0.3.6';
+	unless http_get('/njs') =~ /^([.0-9]+)$/m && $1 ge '0.3.6';
 
 like(http(
 	'GET /hdr_in HTTP/1.0' . CRLF
@@ -270,7 +398,7 @@
 
 TODO: {
 local $TODO = 'not yet'
-               unless http_get('/njs') =~ /^([.0-9]+)$/m && $1 ge '0.3.7';
+	unless http_get('/njs') =~ /^([.0-9]+)$/m && $1 ge '0.3.7';
 
 like(http(
 	'GET /hdr_sorted_keys?in=1 HTTP/1.0' . CRLF