Implement String to/from ByteArray conversion (KT-24810)

libraries/stdlib/js/src/kotlin/text/string.kt

@@ -74,6 +74,52 @@ public actual fun String.toCharArray(startIndex: Int = 0, endIndex: Int = this.l
     return CharArray(endIndex - startIndex) { get(startIndex + it) }
 }
 
+/**
+ * Decodes a string from the bytes in UTF-8 encoding in this array or its subrange.
+ *
+ * @param startIndex the beginning (inclusive) of the subrange to decode, 0 by default.
+ * @param endIndex the end (exclusive) of the subrange to decode, size of this array by default.
+ * @param throwOnInvalidSequence specifies whether to throw an exception on malformed byte sequence or replace it by the replacement char `\uFFFD`.
+ *
+ * @throws IndexOutOfBoundsException if [startIndex] is less than zero or [endIndex] is greater than the size of this array.
+ * @throws IllegalArgumentException if [startIndex] is greater than [endIndex].
+ * @throws CharacterCodingException if the byte array contains malformed UTF-8 byte sequence and [throwOnInvalidSequence] is true.
+ */
+@SinceKotlin("1.3")
+@Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+@ExperimentalStdlibApi
+public actual fun ByteArray.decodeToString(
+    startIndex: Int = 0,
+    endIndex: Int = this.size,
+    throwOnInvalidSequence: Boolean = false
+): String {
+    AbstractList.checkBoundsIndexes(startIndex, endIndex, this.size)
+    return decodeUtf8(this, startIndex, endIndex, throwOnInvalidSequence)
+}
+
+/**
+ * Encodes this string or its substring to an array of bytes in UTF-8 encoding.
+ *
+ * @param startIndex the beginning (inclusive) of the substring to encode, 0 by default.
+ * @param endIndex the end (exclusive) of the substring to encode, length of this string by default.
+ * @param throwOnInvalidSequence specifies whether to throw an exception on malformed char sequence or replace.
+ *
+ * @throws IndexOutOfBoundsException if [startIndex] is less than zero or [endIndex] is greater than the length of this string.
+ * @throws IllegalArgumentException if [startIndex] is greater than [endIndex].
+ * @throws CharacterCodingException if this string contains malformed char sequence and [throwOnInvalidSequence] is true.
+ */
+@SinceKotlin("1.3")
+@Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+@ExperimentalStdlibApi
+public actual fun String.encodeToByteArray(
+    startIndex: Int = 0,
+    endIndex: Int = this.length,
+    throwOnInvalidSequence: Boolean = false
+): ByteArray {
+    AbstractList.checkBoundsIndexes(startIndex, endIndex, length)
+    return encodeUtf8(this, startIndex, endIndex, throwOnInvalidSequence)
+}
+
 /**
  * Returns a copy of this string converted to upper case using the rules of the default locale.
  *