diff --git a/js/js.libraries/src/core/string.kt b/js/js.libraries/src/core/string.kt
index 853647ebe53..4bbdcca4617 100644
--- a/js/js.libraries/src/core/string.kt
+++ b/js/js.libraries/src/core/string.kt
@@ -7,20 +7,16 @@ native public fun String.toUpperCase() : String = noImpl
 
 native public fun String.toLowerCase() : String = noImpl
 
-// TODO: make internal
 native("indexOf")
-public fun String.nativeIndexOf(str : String, fromIndex : Int) : Int = noImpl
+internal fun String.nativeIndexOf(str : String, fromIndex : Int) : Int = noImpl
 
-// TODO: make internal
 native("lastIndexOf")
-public fun String.nativeLastIndexOf(str : String, fromIndex : Int) : Int = noImpl
+internal fun String.nativeLastIndexOf(str : String, fromIndex : Int) : Int = noImpl
 
-// TODO: make internal
 native("startsWith")
-public fun String.nativeStartsWith(s: String, position: Int): Boolean = noImpl
-// TODO: make internal
+internal fun String.nativeStartsWith(s: String, position: Int): Boolean = noImpl
 native("endsWith")
-public fun String.nativeEndsWith(s: String): Boolean = noImpl
+internal fun String.nativeEndsWith(s: String): Boolean = noImpl
 
 deprecated("Use split(Regex) instead.")
 library("splitString")
@@ -57,9 +53,8 @@ public fun CharSequence.isEmpty(): Boolean = noImpl
 
 
 
-// TODO: internal
 native("replace")
-public fun String.nativeReplace(pattern: RegExp, replacement: String): String = noImpl
+internal fun String.nativeReplace(pattern: RegExp, replacement: String): String = noImpl
 
 
 /*
diff --git a/js/js.libraries/src/core/stringsCode.kt b/js/js.libraries/src/core/stringsCode.kt
index fe8b60cca05..8ac42c0883a 100644
--- a/js/js.libraries/src/core/stringsCode.kt
+++ b/js/js.libraries/src/core/stringsCode.kt
@@ -3,9 +3,8 @@ package kotlin
 import kotlin.text.Regex
 import kotlin.text.js.RegExp
 
-// TODO: make internal
-public inline fun String.nativeIndexOf(ch : Char, fromIndex : Int) : Int = nativeIndexOf(ch.toString(), fromIndex)
-public inline fun String.nativeLastIndexOf(ch : Char, fromIndex : Int) : Int = nativeLastIndexOf(ch.toString(), fromIndex)
+internal inline fun String.nativeIndexOf(ch : Char, fromIndex : Int) : Int = nativeIndexOf(ch.toString(), fromIndex)
+internal inline fun String.nativeLastIndexOf(ch : Char, fromIndex : Int) : Int = nativeLastIndexOf(ch.toString(), fromIndex)
 
 /**
  * Returns `true` if this string starts with the specified prefix.