diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000..504afef81
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+node_modules/
+package-lock.json
diff --git a/.hgignore b/.hgignore
new file mode 100644
index 000000000..4ef133f11
--- /dev/null
+++ b/.hgignore
@@ -0,0 +1,2 @@
+/node_modules/
+package-lock.json
diff --git a/auto/make b/auto/make
index 4ec533fee..871354ff5 100644
--- a/auto/make
+++ b/auto/make
@@ -19,6 +19,11 @@ NJS_STATIC_LINK = ${AR} -r -c
 NJS_LINK = ${CC} ${NJS_LD_OPT}
 NJS_CFLAGS = ${NJS_CFLAGS} ${NJS_CC_OPT} ${CFLAGS}
 
+NJS_VER = $(grep NJS_VERSION src/njs.h | sed -e 's/.*"\(.*\)".*/\1/')
+NJS_TYPES_VER ?= \$(NJS_VER)
+
+NPM = npm
+
 default: $NJS_DEFAULT_TARGET
 END
 
@@ -260,21 +265,50 @@ benchmark: $NJS_BUILD_DIR/njs_auto_config.h \\
 
 	$NJS_BUILD_DIR/njs_benchmark
 
-ts:
-	mkdir -p $NJS_BUILD_DIR/ts
-	cp nginx/ts/*.ts $NJS_BUILD_DIR/ts/
-	cp src/ts/*.ts $NJS_BUILD_DIR/ts/
+$NJS_BUILD_DIR/ts/package.json: $NJS_TS_SRCS
+	cp -fr ts $NJS_BUILD_DIR/
+	cp LICENSE $NJS_BUILD_DIR/ts/
+	sed 's/\("version":\s*\)"\([^"]\+\)"/\1"\$(NJS_TYPES_VER)"/' \\
+		ts/package.json > $NJS_BUILD_DIR/ts/package.json
+
+$NJS_BUILD_DIR/ts/node_modules: $NJS_BUILD_DIR/ts/package.json
+	cd $NJS_BUILD_DIR/ts && \$(NPM) install
+	touch $NJS_BUILD_DIR/ts/node_modules
+
+$NJS_BUILD_DIR/njs-types-\$(NJS_TYPES_VER).tgz: $NJS_BUILD_DIR/ts/package.json
+	hg id -i > $NJS_BUILD_DIR/ts/COMMITHASH || true
+	cd $NJS_BUILD_DIR && \$(NPM) pack ./ts
+
+$NJS_BUILD_DIR/test/ts/package.json: $NJS_TS_TEST_SRCS
+	mkdir -p $NJS_BUILD_DIR/test
+	cp -fr test/ts $NJS_BUILD_DIR/test/
+
+$NJS_BUILD_DIR/test/ts/node_modules: $NJS_BUILD_DIR/njs-types-\$(NJS_TYPES_VER).tgz $NJS_BUILD_DIR/test/ts/package.json
+	cd $NJS_BUILD_DIR/test/ts && \$(NPM) install --save-dev file:../../njs-types-\$(NJS_TYPES_VER).tgz
+	cd $NJS_BUILD_DIR/test/ts && \$(NPM) install
+	touch $NJS_BUILD_DIR/test/ts/node_modules
+
+.PHONY: ts
+ts: $NJS_BUILD_DIR/ts/package.json
+
+ts_lint: $NJS_BUILD_DIR/ts/node_modules
+	cd $NJS_BUILD_DIR/ts && \$(NPM) run lint
+
+ts_test: $NJS_BUILD_DIR/test/ts/node_modules
+	cd $NJS_BUILD_DIR/test/ts && \$(NPM) test
+
+ts_publish: ts_clean $NJS_BUILD_DIR/njs-types-\$(NJS_TYPES_VER).tgz
+	\$(NPM) publish $<
 
-ts_test: ts
-	tsc ./test/ts/test.ts
+ts_clean:
+	rm -rf $NJS_BUILD_DIR/ts $NJS_BUILD_DIR/test/ts
 
 dist:
-	NJS_VER=`grep NJS_VERSION src/njs.h | sed -e 's/.*"\(.*\)".*/\1/'`; \\
-	rm -rf njs-\$\${NJS_VER} \\
-	&& hg archive njs-\$\${NJS_VER}.tar.gz \\
-		-p njs-\$\${NJS_VER} \\
+	rm -rf njs-\$(NJS_VER) \\
+	&& hg archive njs-\$(NJS_VER).tar.gz \\
+		-p njs-\$(NJS_VER) \\
 		-X ".hg*" \\
-	&& echo njs-\$\${NJS_VER}.tar.gz done
+	&& echo njs-\$(NJS_VER).tar.gz done
 END
 
 
diff --git a/auto/sources b/auto/sources
index 418a4d611..22622b00a 100644
--- a/auto/sources
+++ b/auto/sources
@@ -71,3 +71,7 @@ NJS_TEST_SRCS=" \
    src/test/njs_unit_test.c \
    src/test/njs_benchmark.c \
 "
+
+NJS_TS_SRCS=$(find ts/ -name "*.d.ts" -o -name "*.json" | xargs)
+
+NJS_TS_TEST_SRCS=$(find test/ts/ -name "*.ts" -o -name "*.json" | xargs)
diff --git a/test/ts/package.json b/test/ts/package.json
new file mode 100644
index 000000000..3daeea81c
--- /dev/null
+++ b/test/ts/package.json
@@ -0,0 +1,15 @@
+{
+  "private": true,
+  "name": "njs-types-test",
+  "version": "0.0.0",
+  "description": "Tests for njs TypeScript type definitions.",
+  "scripts": {
+    "test": "tsc"
+  },
+  "author": "NGINX, Inc.",
+  "license": "BSD-2-Clause",
+  "devDependencies": {
+    "njs-types": "file:../../ts",
+    "typescript": "~4.0.3"
+  }
+}
diff --git a/test/ts/test.ts b/test/ts/test.ts
index dbb8df7b7..ce7940ded 100644
--- a/test/ts/test.ts
+++ b/test/ts/test.ts
@@ -1,8 +1,3 @@
-/// <reference path="../../build/ts/ngx_http_js_module.d.ts" />
-/// <reference path="../../build/ts/fs.d.ts" />
-/// <reference path="../../build/ts/querystring.d.ts" />
-/// <reference path="../../build/ts/crypto.d.ts" />
-
 import fs from 'fs';
 import qs from 'querystring';
 import crypto from 'crypto';
@@ -15,9 +10,9 @@ function http_module(r: NginxHTTPRequest) {
 
     s = 'ordinary string';
     bs = String.bytesFrom('000000', 'hex');
-    bs = s.toBytes();
+    var bs2: NjsByteString | null = s.toBytes();
     bs = s.toUTF8();
-    bs.fromBytes(null, null);
+    bs.fromBytes(undefined, undefined);
 
     s = bs + '';
 
@@ -30,29 +25,30 @@ function http_module(r: NginxHTTPRequest) {
 
     bs = r.args.x;
     bs = r.args[1];
-    s = r.args.x.fromUTF8();
+    var s2: string | null = r.args.x.fromUTF8();
     s = r.args.x + '';
 
     // r.headersIn
 
-    r.headersIn['Accept'].fromBytes() == 'dddd';
+    r.headersIn['Accept']?.fromBytes() == 'dddd';
 
     // r.headersOut
 
     r.headersOut['Content-Type'] = 'text/plain';
     // Warning: r.headersOut['Content-Type'] = ['a', 'b'];
     r.headersOut['Connection'] = undefined;
-    r.headersOut['Connection'] = null;
+
+    delete r.headersOut['Bar'];
 
     r.headersOut['Set-Cookie'] = ['aaa', 'bbb'];
     r.headersOut['Foo'] = ['aaa', 'bbb'];
 
-    r.subrequest('/uri', reply => r.return(200, reply.headersOut["Location"]));
+    r.subrequest('/uri', reply => r.return(200, reply.headersOut["Location"] ?? ''));
 
     // r.log
 
     r.log(bs);
-    r.log(r.headersOut['Connection']);
+    r.log(r.headersOut['Connection'] ?? '');
 
     // r.variables
 
@@ -64,7 +60,7 @@ function http_module(r: NginxHTTPRequest) {
     r.subrequest('/p/sub2', reply => r.return(reply.status));
     r.subrequest('/p/sub3', {detached:true});
     r.subrequest('/p/sub4', 'a=1&b=2').then(reply => r.return(reply.status,
-                                        JSON.stringify(JSON.parse(reply.responseBody))));
+                                        JSON.stringify(JSON.parse(reply.responseBody ?? ''))));
 
 }
 
diff --git a/test/ts/tsconfig.json b/test/ts/tsconfig.json
new file mode 100644
index 000000000..f11f689a5
--- /dev/null
+++ b/test/ts/tsconfig.json
@@ -0,0 +1,35 @@
+{
+    "compilerOptions": {
+        "target": "ES5",
+        "module": "es2015",
+        "lib": [
+            "ES2015",
+            "ES2016.Array.Include",
+            "ES2017.Object",
+            "ES2017.String"
+        ],
+        "noEmit": true,
+        "downlevelIteration": true,
+
+        "strict": true,
+        "noImplicitAny": true,
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "strictBindCallApply": true,
+        "strictPropertyInitialization": true,
+        "noImplicitThis": true,
+        "alwaysStrict": true,
+
+        "moduleResolution": "node",
+        "forceConsistentCasingInFileNames": true
+    },
+    "include": [
+        "**/*.ts"
+    ],
+    "exclude": [
+        "./node_modules/**"
+    ],
+    "files": [
+        "./node_modules/njs-types/ngx_http_js_module.d.ts"
+    ]
+}
diff --git a/ts/README.md b/ts/README.md
new file mode 100644
index 000000000..de28f6d6b
--- /dev/null
+++ b/ts/README.md
@@ -0,0 +1,79 @@
+# TypeScript definitions for njs
+
+This package contains type definitions for [njs](https://github.com/nginx/njs) – NGINX JavaScript.
+
+
+## Usage
+
+Install **njs-types** from the [npm registry](https://www.npmjs.com/) into your project:
+
+```sh
+# using npm:
+npm install --save-dev njs-types
+# or using yarn:
+yarn add --dev njs-types
+```
+
+njs-types provides three entry points with global declarations for each of njs environments:
+
+* `njs_shell.d.ts` – njs shell
+* `ngx_http_js_module.d.ts` – NGINX JS HTTP Module
+* `ngx_stream_js_module.d.ts` – NGINX JS Stream Module
+
+You can either reference them using [triple-slash directive](https://www.typescriptlang.org/docs/handbook/triple-slash-directives.html) at top of your `.ts` files (adjust `path` to point into your project’s node_modules):
+
+```ts
+/// <reference path="./node_modules/njs-types/ngx_http_js_module.d.ts" />
+```
+
+or include them using the [files](https://www.typescriptlang.org/tsconfig#files) flag in your `tsconfig.json`, for example:
+
+```json
+{
+  "compilerOptions": {
+    "target": "ES5",
+    "module": "es2015",
+    "lib": [
+      "ES2015",
+      "ES2016.Array.Include",
+      "ES2017.Object",
+      "ES2017.String",
+    ],
+    "outDir": "./lib",
+    "downlevelIteration": true,
+
+    "strict": true,
+    "noImplicitAny": true,
+    "strictNullChecks": true,
+    "strictFunctionTypes": true,
+    "strictBindCallApply": true,
+    "strictPropertyInitialization": true,
+    "noImplicitThis": true,
+    "alwaysStrict": true,
+
+    "moduleResolution": "node",
+
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+  },
+  "include": [
+    "./src",
+  ],
+  "files": [
+    "./node_modules/njs-types/ngx_http_js_module.d.ts",
+  ],
+}
+```
+
+
+## Versions
+
+njs-types is typically being released together with njs.
+Their major and minor release numbers (the first two numbers) are always aligned, but the patch version (the third number) may differ.
+That's because njs-types may be updated between njs releases and in such case the patch version is incremented.
+
+It's the same strategy as used in [DefinitelyTyped](https://github.com/DefinitelyTyped/DefinitelyTyped#how-do-definitely-typed-package-versions-relate-to-versions-of-the-corresponding-library).
+The reason is that npmjs enforces [SemVer](https://semver.org/) which doesn't allow four-part version number nor provide post-release suffixes.
+
+You can find from which commit the package was built in file `COMMITHASH` inside the published package.
+It contains global revision id in the upstream repository https://hg.nginx.org/njs/ (Mercurial).
diff --git a/ts/index.d.ts b/ts/index.d.ts
new file mode 100644
index 000000000..8a324cc6c
--- /dev/null
+++ b/ts/index.d.ts
@@ -0,0 +1,4 @@
+/// <reference path="njs_core.d.ts" />
+/// <reference path="njs_modules/crypto.d.ts" />
+/// <reference path="njs_modules/fs.d.ts" />
+/// <reference path="njs_modules/querystring.d.ts" />
diff --git a/nginx/ts/ngx_http_js_module.d.ts b/ts/ngx_http_js_module.d.ts
similarity index 98%
rename from nginx/ts/ngx_http_js_module.d.ts
rename to ts/ngx_http_js_module.d.ts
index d29b1385c..c6b94e4f6 100644
--- a/nginx/ts/ngx_http_js_module.d.ts
+++ b/ts/ngx_http_js_module.d.ts
@@ -1,4 +1,4 @@
-/// <reference path="njs_core.d.ts" />
+/// <reference path="index.d.ts" />
 
 interface NginxHTTPArgs {
     readonly [prop: string]: NjsByteString;
@@ -39,7 +39,7 @@ interface NginxHeadersIn {
     readonly 'Warning'?: NjsByteString;
     readonly 'X-Forwarded-For'?: NjsByteString;
 
-    readonly [prop: string]: NjsByteString;
+    readonly [prop: string]: NjsByteString | undefined;
 }
 
 interface NginxHeadersOut {
@@ -76,7 +76,7 @@ interface NginxHeadersOut {
 
     'Set-Cookie'?: NjsStringLike[];
 
-    [prop: string]: NjsStringLike | NjsStringLike[];
+    [prop: string]: NjsStringLike | NjsStringLike[] | undefined;
 }
 
 interface NginxVariables {
@@ -229,7 +229,7 @@ interface NginxVariables {
     readonly 'upstream_trailer_'?: NjsByteString;
     readonly 'uri'?: NjsByteString;
 
-    [prop: string]: NjsStringLike;
+    [prop: string]: NjsStringLike | undefined;
 }
 
 interface NginxSubrequestOptions {
diff --git a/nginx/ts/ngx_stream_js_module.d.ts b/ts/ngx_stream_js_module.d.ts
similarity index 98%
rename from nginx/ts/ngx_stream_js_module.d.ts
rename to ts/ngx_stream_js_module.d.ts
index 47799ba23..46aa76dd6 100644
--- a/nginx/ts/ngx_stream_js_module.d.ts
+++ b/ts/ngx_stream_js_module.d.ts
@@ -1,4 +1,4 @@
-/// <reference path="njs_core.d.ts" />
+/// <reference path="index.d.ts" />
 
 interface NginxStreamVariables {
     readonly 'binary_remote_addr'?: NjsByteString;
@@ -66,7 +66,7 @@ interface NginxStreamVariables {
     readonly 'time_iso8601'?: NjsByteString;
     readonly 'time_local'?: NjsByteString;
 
-    [prop: string]: NjsByteString;
+    [prop: string]: NjsByteString | undefined;
 }
 
 interface NginxStreamCallbackFlags {
diff --git a/src/ts/njs_core.d.ts b/ts/njs_core.d.ts
similarity index 100%
rename from src/ts/njs_core.d.ts
rename to ts/njs_core.d.ts
diff --git a/src/ts/crypto.d.ts b/ts/njs_modules/crypto.d.ts
similarity index 98%
rename from src/ts/crypto.d.ts
rename to ts/njs_modules/crypto.d.ts
index 5895b3e74..345a2d1a7 100644
--- a/src/ts/crypto.d.ts
+++ b/ts/njs_modules/crypto.d.ts
@@ -1,4 +1,4 @@
-/// <reference path="njs_core.d.ts" />
+/// <reference path="../njs_core.d.ts" />
 
 declare module "crypto" {
 
diff --git a/src/ts/fs.d.ts b/ts/njs_modules/fs.d.ts
similarity index 99%
rename from src/ts/fs.d.ts
rename to ts/njs_modules/fs.d.ts
index 682cee490..cc24f243a 100644
--- a/src/ts/fs.d.ts
+++ b/ts/njs_modules/fs.d.ts
@@ -1,4 +1,4 @@
-/// <reference path="njs_core.d.ts" />
+/// <reference path="../njs_core.d.ts" />
 
 declare module "fs" {
 
diff --git a/src/ts/querystring.d.ts b/ts/njs_modules/querystring.d.ts
similarity index 99%
rename from src/ts/querystring.d.ts
rename to ts/njs_modules/querystring.d.ts
index 0368ec1c4..4058f5a1c 100644
--- a/src/ts/querystring.d.ts
+++ b/ts/njs_modules/querystring.d.ts
@@ -1,4 +1,4 @@
-/// <reference path="njs_core.d.ts" />
+/// <reference path="../njs_core.d.ts" />
 
 declare module "querystring" {
 
diff --git a/src/ts/njs_shell.d.ts b/ts/njs_shell.d.ts
similarity index 70%
rename from src/ts/njs_shell.d.ts
rename to ts/njs_shell.d.ts
index 3a6aa5ed6..e81802584 100644
--- a/src/ts/njs_shell.d.ts
+++ b/ts/njs_shell.d.ts
@@ -1,4 +1,4 @@
-/// <reference path="njs_core.d.ts" />
+/// <reference path="index.d.ts" />
 
 interface Console {
     log(...args: any[]): void;
@@ -7,3 +7,5 @@ interface Console {
     time(label?: NjsStringLike): void;
     timeEnd(label?: NjsStringLike): void;
 }
+
+declare const console: Console;
diff --git a/ts/package.json b/ts/package.json
new file mode 100644
index 000000000..e7b2eb779
--- /dev/null
+++ b/ts/package.json
@@ -0,0 +1,31 @@
+{
+  "name": "njs-types",
+  "version": "0.0.0-dev",
+  "description": "TypeScript definitions for njs scripting language and nginx js modules.",
+  "scripts": {
+    "lint": "tsc"
+  },
+  "files": [
+    "**/*.d.ts",
+    "COMMITHASH"
+  ],
+  "types": "index.d.ts",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/nginx/njs.git"
+  },
+  "keywords": [
+    "nginx",
+    "njs",
+    "types"
+  ],
+  "author": "NGINX, Inc.",
+  "license": "BSD-2-Clause",
+  "bugs": {
+    "url": "https://github.com/nginx/njs/issues"
+  },
+  "homepage": "https://nginx.org/en/docs/njs/",
+  "devDependencies": {
+    "typescript": "^4.0.3"
+  }
+}
diff --git a/ts/tsconfig.json b/ts/tsconfig.json
new file mode 100644
index 000000000..b9a969a9a
--- /dev/null
+++ b/ts/tsconfig.json
@@ -0,0 +1,25 @@
+{
+    "compilerOptions": {
+        "target": "ES5",
+        "module": "es2015",
+        "lib": [
+            "ES2015",
+            "ES2016.Array.Include",
+            "ES2017.Object",
+            "ES2017.String"
+        ],
+        "noEmit": true,
+        "downlevelIteration": true,
+        "strict": true,
+        "noImplicitAny": true,
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "strictBindCallApply": true,
+        "strictPropertyInitialization": true,
+        "noImplicitThis": true,
+        "alwaysStrict": true,
+
+        "moduleResolution": "node",
+        "forceConsistentCasingInFileNames": true
+    }
+}