diff --git a/libraries/stdlib/common/src/kotlin/TextH.kt b/libraries/stdlib/common/src/kotlin/TextH.kt
index b5a4009e5d4..2d0a6305d64 100644
--- a/libraries/stdlib/common/src/kotlin/TextH.kt
+++ b/libraries/stdlib/common/src/kotlin/TextH.kt
@@ -100,6 +100,9 @@ public expect fun String(chars: CharArray): String
 
 /**
  * Converts the characters from a portion of the specified array to a string.
+ *
+ * @throws IndexOutOfBoundsException if either [offset] or [length] are less than zero
+ * or `offset + length` is out of [chars] array bounds.
  */
 @SinceKotlin("1.2")
 public expect fun String(chars: CharArray, offset: Int, length: Int): String
diff --git a/libraries/stdlib/js/src/kotlin/string.kt b/libraries/stdlib/js/src/kotlin/string.kt
index 1f20bf6d13c..74c8a52dd06 100644
--- a/libraries/stdlib/js/src/kotlin/string.kt
+++ b/libraries/stdlib/js/src/kotlin/string.kt
@@ -11,17 +11,29 @@ import kotlin.js.RegExp
  * Converts the characters in the specified array to a string.
  */
 @SinceKotlin("1.2")
-@kotlin.internal.InlineOnly
-public actual inline fun String(chars: CharArray): String {
-    return js("String.fromCharCode").apply(null, chars)
+public actual fun String(chars: CharArray): String {
+    var result = ""
+    for (char in chars) {
+        result += char
+    }
+    return result
 }
 
 /**
  * Converts the characters from a portion of the specified array to a string.
+ *
+ * @throws IndexOutOfBoundsException if either [offset] or [length] are less than zero
+ * or `offset + length` is out of [chars] array bounds.
  */
 @SinceKotlin("1.2")
 public actual fun String(chars: CharArray, offset: Int, length: Int): String {
-    return String(chars.copyOfRange(offset, offset + length))
+    if (offset < 0 || length < 0 || chars.size - offset < length)
+        throw IndexOutOfBoundsException("size: ${chars.size}; offset: $offset; length: $length")
+    var result = ""
+    for (index in offset until offset + length) {
+        result += chars[index]
+    }
+    return result
 }
 
 /**
diff --git a/libraries/stdlib/jvm/src/kotlin/text/StringsJVM.kt b/libraries/stdlib/jvm/src/kotlin/text/StringsJVM.kt
index b2bd93fece7..0a9d375780f 100644
--- a/libraries/stdlib/jvm/src/kotlin/text/StringsJVM.kt
+++ b/libraries/stdlib/jvm/src/kotlin/text/StringsJVM.kt
@@ -272,6 +272,9 @@ public actual inline fun String(chars: CharArray): String =
 
 /**
  * Converts the characters from a portion of the specified array to a string.
+ *
+ * @throws IndexOutOfBoundsException if either [offset] or [length] are less than zero
+ * or `offset + length` is out of [chars] array bounds.
  */
 @kotlin.internal.InlineOnly
 public actual inline fun String(chars: CharArray, offset: Int, length: Int): String =
diff --git a/libraries/stdlib/test/text/StringTest.kt b/libraries/stdlib/test/text/StringTest.kt
index a163296af67..ded4bc92967 100644
--- a/libraries/stdlib/test/text/StringTest.kt
+++ b/libraries/stdlib/test/text/StringTest.kt
@@ -53,11 +53,21 @@ class StringTest {
     @Test fun stringFromCharArraySlice() {
         val chars: CharArray = charArrayOf('K', 'o', 't', 'l', 'i', 'n', ' ', 'r', 'u', 'l', 'e', 's')
         assertEquals("rule", String(chars, 7, 4))
+
+        val longChars = CharArray(200_000) { 'k' }
+        val longString = String(longChars, 1000, 190_000)
+        assertEquals(190_000, longString.length)
+        assertTrue(longString.all { it == 'k' })
     }
 
     @Test fun stringFromCharArray() {
         val chars: CharArray = charArrayOf('K', 'o', 't', 'l', 'i', 'n')
         assertEquals("Kotlin", String(chars))
+
+        val longChars = CharArray(200_000) { 'k' }
+        val longString = String(longChars)
+        assertEquals(200_000, longString.length)
+        assertTrue(longString.all { it == 'k' })
     }
 
     @Test fun stringFromCharArrayUnicodeSurrogatePairs() {
@@ -67,6 +77,16 @@ class StringTest {
         assertEquals("Ŭᎍ🀺", String(chars, 3, 4))
     }
 
+    @Test fun stringFromCharArrayOutOfBounds() {
+        fun test(chars: CharArray) {
+            assertFailsWith<IndexOutOfBoundsException> { String(chars, -1, 1) }
+            assertFailsWith<IndexOutOfBoundsException> { String(chars, 1, -1) }
+            assertFailsWith<IndexOutOfBoundsException> { String(chars, chars.size - 1, 2) }
+        }
+        test(CharArray(16) { 'k' })
+        test(CharArray(160_000) { 'k' })
+    }
+
     @Test fun isEmptyAndBlank() = withOneCharSequenceArg { arg1 ->
         class Case(val value: String?, val isNull: Boolean = false, val isEmpty: Boolean = false, val isBlank: Boolean = false)