new file mode 100644
--- /dev/null
+++ b/js_preload_object.t
@@ -0,0 +1,181 @@
+#!/usr/bin/perl
+
+# (C) Vadim Zhestikov
+# (C) Nginx, Inc.
+
+# Tests for http njs module, js_preload_object directive.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+my $t = Test::Nginx->new()->has(qw/http rewrite/)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    js_preload_object g1 from g.json;
+    js_preload_object ga from ga.json;
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        js_import lib.js;
+        js_preload_object lx from l.json;
+
+        location /test {
+            js_content lib.test;
+        }
+
+        location /test_query {
+            js_import lib1.js;
+            js_content lib1.query;
+        }
+
+        location /test_query_preloaded {
+            js_import lib1.js;
+            js_preload_object l.json;
+            js_content lib1.query;
+        }
+
+        location /test_var {
+            js_set $test_var lib.test_var;
+            return 200 $test_var;
+        }
+
+        location /test_mutate {
+            js_content lib.mutate;
+        }
+
+        location /test_no_suffix {
+            js_preload_object gg from no_suffix;
+            js_content lib.suffix;
+        }
+    }
+}
+
+EOF
+
+$t->write_file('lib.js', <<EOF);
+    function test(r) {
+        r.return(200, ga + ' ' + g1.c.prop[0].a + ' ' + lx);
+    }
+
+    function test_var(r) {
+        return g1.b[2];
+    }
+
+    function mutate(r) {
+        var res = "OK";
+
+        try {
+            switch (r.args.method) {
+            case 'set_obj':
+                g1.c.prop[0].a = 5;
+                break;
+            case 'set_arr':
+                g1.c.prop[0] = 5;
+                break;
+            case 'add_obj':
+                g1.c.prop[0].xxx = 5;
+                break;
+            case 'add_arr':
+                g1.c.prop[10] = 5;
+                break;
+            case 'del_obj':
+                delete g1.c.prop[0].a;
+                break;
+            case 'del_arr':
+                delete g1.c.prop[0];
+                break;
+            }
+
+        } catch (e) {
+            res = e.message;
+        }
+
+        r.return(200, res);
+    }
+
+    function suffix(r) {
+        r.return(200, gg);
+    }
+
+    export default {test, test_var, mutate, suffix};
+
+EOF
+
+$t->write_file('lib1.js', <<EOF);
+    function query(r) {
+        var res = 'ok';
+
+        try {
+            res = r.args.path.split('.').reduce((a, v) => a[v], globalThis);
+
+        } catch (e) {
+            res = e.message;
+        }
+
+        r.return(200, njs.dump(res));
+    }
+
+    export default {query};
+
+EOF
+
+$t->write_file('g.json',
+	'{"a":1, "b":[1,2,"element",4,5], "c":{"prop":[{"a":2}]}}');
+$t->write_file('ga.json', '"ga loaded"');
+$t->write_file('l.json', '"l loaded"');
+$t->write_file('no_suffix', '"no_suffix loaded"');
+
+$t->try_run('no js_preload_object available')->plan(12);
+
+###############################################################################
+
+like(http_get('/test'), qr/ga loaded 2 l loaded/s, 'direct query');
+like(http_get('/test_query?path=l'), qr/undefined/s, 'unreferenced');
+like(http_get('/test_query_preloaded?path=l'), qr/l loaded/s,
+	'reference preload');
+like(http_get('/test_query?path=g1.b.1'), qr/2/s, 'complex query');
+like(http_get('/test_var'), qr/element/s, 'var reference');
+
+like(http_get('/test_mutate?method=set_obj'), qr/Cannot assign to read-only/s,
+	'preload_object props are const (object)');
+like(http_get('/test_mutate?method=set_arr'), qr/Cannot assign to read-only/s,
+	'preload_object props are const (array)');
+like(http_get('/test_mutate?method=add_obj'), qr/Cannot add property "xxx"/s,
+	'preload_object props are not extensible (object)');
+like(http_get('/test_mutate?method=add_arr'), qr/Cannot add property "10"/s,
+	'preload_object props are not extensible (array)');
+like(http_get('/test_mutate?method=del_obj'), qr/Cannot delete property "a"/s,
+	'preload_object props are not deletable (object)');
+like(http_get('/test_mutate?method=del_arr'), qr/Cannot delete property "0"/s,
+	'preload_object props are not deletable (array)');
+
+like(http_get('/test_no_suffix'), qr/no_suffix loaded/s,
+	'load without suffix');
+
+###############################################################################

new file mode 100644
--- /dev/null
+++ b/stream_js_preload_object.t
@@ -0,0 +1,122 @@
+#!/usr/bin/perl
+
+# (C) Vadim Zhestikov
+# (C) Nginx, Inc.
+
+# Tests for stream njs module, js_preload_object directive.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+use Test::Nginx::Stream qw/ stream /;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+my $t = Test::Nginx->new()->has(qw/stream stream_return/)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+stream {
+    %%TEST_GLOBALS_STREAM%%
+
+    js_preload_object g1 from g.json;
+
+    js_set $test foo.bar.p;
+
+    js_import lib.js;
+    js_import foo from ./main.js;
+
+    server {
+        listen  127.0.0.1:8081;
+        return  $test;
+    }
+
+    server {
+        listen      127.0.0.1:8082;
+        js_access   lib.access;
+        js_preread  lib.preread;
+        js_filter   lib.filter;
+        proxy_pass  127.0.0.1:8083;
+    }
+
+    server {
+        listen  127.0.0.1:8083;
+        return  "x";
+    }
+}
+
+EOF
+
+$t->write_file('lib.js', <<EOF);
+    var res = '';
+
+    function access(s) {
+        res += g1.a;
+        s.allow();
+    }
+
+    function preread(s) {
+        s.on('upload', function (data) {
+            res += g1.b[1];
+            if (res.length >= 3) {
+                s.done();
+            }
+        });
+    }
+
+    function filter(s) {
+        s.on('upload', function(data, flags) {
+            s.send(data);
+            res += g1.c.prop[0].a;
+        });
+
+        s.on('download', function(data, flags) {
+            if (!flags.last) {
+                res += g1.b[3];
+                s.send(data);
+
+            } else {
+                res += g1.b[4];
+                s.send(res, {last:1});
+                s.off('download');
+            }
+        });
+    }
+
+    export default {access, preread, filter};
+
+EOF
+
+$t->write_file('main.js', <<EOF);
+    export default {bar: {p(s) {return g1.b[2]}}};
+
+EOF
+
+$t->write_file('g.json',
+	'{"a":1, "b":[1,2,"element",4,5], "c":{"prop":[{"a":3}]}}');
+
+$t->try_run('no js_preload_object available')->plan(2);
+
+###############################################################################
+
+is(stream('127.0.0.1:' . port(8081))->read(), 'element', 'foo.bar.p');
+is(stream('127.0.0.1:' . port(8082))->io('0'), 'x122345', 'lib.access');
+
+###############################################################################