diff --git a/src/asStream.js b/src/asStream.js
index b6e9f9b..ca95525 100644
--- a/src/asStream.js
+++ b/src/asStream.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./asStream.d.ts"
+
 'use strict';
 
 const {Duplex} = require('node:stream');
diff --git a/src/defs.js b/src/defs.js
index 9538719..9fc331d 100644
--- a/src/defs.js
+++ b/src/defs.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./defs.d.ts"
+
 'use strict';
 
 const none = Symbol.for('object-stream.none');
diff --git a/src/fun.js b/src/fun.js
index 6ac64c7..bc2fc8c 100644
--- a/src/fun.js
+++ b/src/fun.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./fun.d.ts"
+
 'use strict';
 
 const defs = require('./defs');
diff --git a/src/gen.js b/src/gen.js
index 4106002..c6cef81 100644
--- a/src/gen.js
+++ b/src/gen.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./gen.d.ts"
+
 'use strict';
 
 const defs = require('./defs');
diff --git a/src/index.js b/src/index.js
index 600972b..aa4520d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./index.d.ts"
+
 'use strict';
 
 const {Readable, Writable, Duplex} = require('node:stream');
diff --git a/src/jsonl/parser.js b/src/jsonl/parser.js
index 2e01437..a97b4cf 100644
--- a/src/jsonl/parser.js
+++ b/src/jsonl/parser.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./parser.d.ts"
+
 'use strict';
 
 const gen = require('../gen.js');
diff --git a/src/jsonl/parserStream.js b/src/jsonl/parserStream.js
index 6b19db0..9286c5b 100644
--- a/src/jsonl/parserStream.js
+++ b/src/jsonl/parserStream.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./parserStream.d.ts"
+
 'use strict';
 
 const gen = require('../gen');
diff --git a/src/jsonl/stringerStream.js b/src/jsonl/stringerStream.js
index 64950db..98823cc 100644
--- a/src/jsonl/stringerStream.js
+++ b/src/jsonl/stringerStream.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./stringerStream.d.ts"
+
 'use strict';
 
 const {Transform} = require('node:stream');
diff --git a/src/utils/batch.js b/src/utils/batch.js
index 373c873..acd9e5c 100644
--- a/src/utils/batch.js
+++ b/src/utils/batch.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./batch.d.ts"
+
 'use strict';
 
 const {none, flushable} = require('../defs');
diff --git a/src/utils/fixUtf8Stream.js b/src/utils/fixUtf8Stream.js
index 685cd8d..e8cffd5 100644
--- a/src/utils/fixUtf8Stream.js
+++ b/src/utils/fixUtf8Stream.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./fixUtf8Stream.d.ts"
+
 'use strict';
 
 const {StringDecoder} = require('string_decoder');
diff --git a/src/utils/fold.js b/src/utils/fold.js
index 5f272ca..5ff3ec6 100644
--- a/src/utils/fold.js
+++ b/src/utils/fold.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./fold.d.ts"
+
 'use strict';
 
 const {none, flushable} = require('../defs');
diff --git a/src/utils/lines.js b/src/utils/lines.js
index 1ec23b0..1d95831 100644
--- a/src/utils/lines.js
+++ b/src/utils/lines.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./lines.d.ts"
+
 'use strict';
 
 const {none, flushable} = require('../defs');
diff --git a/src/utils/readableFrom.js b/src/utils/readableFrom.js
index bf2719a..f0af9cb 100644
--- a/src/utils/readableFrom.js
+++ b/src/utils/readableFrom.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./readableFrom.d.ts"
+
 'use strict';
 
 const {Readable} = require('node:stream');
diff --git a/src/utils/reduce.js b/src/utils/reduce.js
index ebe4f80..7c33555 100644
--- a/src/utils/reduce.js
+++ b/src/utils/reduce.js
@@ -1 +1,3 @@
+// @ts-self-types="./reduce.d.ts"
+
 module.exports = require('./fold');
diff --git a/src/utils/reduceStream.js b/src/utils/reduceStream.js
index 3bf1521..9f7e6f6 100644
--- a/src/utils/reduceStream.js
+++ b/src/utils/reduceStream.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./reduceStream.d.ts"
+
 'use strict';
 
 const {Writable} = require('node:stream');
diff --git a/src/utils/scan.js b/src/utils/scan.js
index b2b3ee4..b75ae15 100644
--- a/src/utils/scan.js
+++ b/src/utils/scan.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./scan.d.ts"
+
 'use strict';
 
 const scan = (fn, acc) => value => {
diff --git a/src/utils/skip.js b/src/utils/skip.js
index f9aea2a..49abeb0 100644
--- a/src/utils/skip.js
+++ b/src/utils/skip.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./skip.d.ts"
+
 'use strict';
 
 const {none} = require('../defs');
diff --git a/src/utils/skipWhile.js b/src/utils/skipWhile.js
index 3ce71cd..b7fb5fd 100644
--- a/src/utils/skipWhile.js
+++ b/src/utils/skipWhile.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./skipWhile.d.ts"
+
 'use strict';
 
 const {none} = require('../defs');
diff --git a/src/utils/take.js b/src/utils/take.js
index 8462e4c..9fefda8 100644
--- a/src/utils/take.js
+++ b/src/utils/take.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./take.d.ts"
+
 'use strict';
 
 const {none} = require('../defs');
diff --git a/src/utils/takeWhile.js b/src/utils/takeWhile.js
index dcb1d95..aaa4202 100644
--- a/src/utils/takeWhile.js
+++ b/src/utils/takeWhile.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./takeWhile.d.ts"
+
 'use strict';
 
 const {none} = require('../defs');
diff --git a/src/utils/takeWithSkip.js b/src/utils/takeWithSkip.js
index 1315343..ab0ee4e 100644
--- a/src/utils/takeWithSkip.js
+++ b/src/utils/takeWithSkip.js
@@ -1,3 +1,5 @@
+// @ts-self-types="./takeWithSkip.d.ts"
+
 'use strict';
 
 const {none} = require('../defs');