diff --git a/lib/fetch/body.js b/lib/fetch/body.js
index 80dab433a97..cc3fa8b7b75 100644
--- a/lib/fetch/body.js
+++ b/lib/fetch/body.js
@@ -16,8 +16,7 @@ const { File } = require('./file')
 const { StringDecoder } = require('string_decoder')
 const { parseMIMEType, serializeAMimeType } = require('./dataURL')
 
-/** @type {globalThis['ReadableStream']} */
-let ReadableStream
+let ReadableStream = globalThis.ReadableStream
 
 // https://fetch.spec.whatwg.org/#concept-bodyinit-extract
 function extractBody (object, keepalive = false) {
diff --git a/lib/fetch/index.js b/lib/fetch/index.js
index a10f1fd9823..8d940c27ca9 100644
--- a/lib/fetch/index.js
+++ b/lib/fetch/index.js
@@ -61,8 +61,7 @@ const { webidl } = require('./webidl')
 
 /** @type {import('buffer').resolveObjectURL} */
 let resolveObjectURL
-/** @type {globalThis['ReadableStream']} */
-let ReadableStream
+let ReadableStream = globalThis.ReadableStream
 
 const nodeVersion = process.versions.node.split('.')
 const nodeMajor = Number(nodeVersion[0])
diff --git a/lib/fetch/request.js b/lib/fetch/request.js
index 533ee91bc10..ce1584ca190 100644
--- a/lib/fetch/request.js
+++ b/lib/fetch/request.js
@@ -29,7 +29,7 @@ const { URLSerializer } = require('./dataURL')
 const { kHeadersList } = require('../core/symbols')
 const assert = require('assert')
 
-let TransformStream
+let TransformStream = globalThis.TransformStream
 
 const kInit = Symbol('init')