Deprecate old Char and String case conversion api #KT-43023

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

@@ -8,7 +8,8 @@ package kotlin.text
 /**
  * Converts this character to lower case using Unicode mapping rules of the invariant locale.
  */
-@OptIn(ExperimentalStdlibApi::class)
+@Deprecated("Use lowercaseChar() instead.", ReplaceWith("lowercaseChar()"))
+@DeprecatedSinceKotlin(warningSince = "1.5")
 @kotlin.internal.InlineOnly
 public actual inline fun Char.toLowerCase(): Char = lowercaseChar()
 
@@ -44,7 +45,8 @@ public actual inline fun Char.lowercase(): String = toString().asDynamic().toLow
 /**
  * Converts this character to upper case using Unicode mapping rules of the invariant locale.
  */
-@OptIn(ExperimentalStdlibApi::class)
+@Deprecated("Use uppercaseChar() instead.", ReplaceWith("uppercaseChar()"))
+@DeprecatedSinceKotlin(warningSince = "1.5")
 @kotlin.internal.InlineOnly
 public actual inline fun Char.toUpperCase(): Char = uppercaseChar()
 

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

@@ -171,6 +171,8 @@ public actual fun String.encodeToByteArray(
 /**
  * Returns a copy of this string converted to upper case using the rules of the default locale.
  */
+@Deprecated("Use uppercase() instead.", ReplaceWith("uppercase()"))
+@DeprecatedSinceKotlin(warningSince = "1.5")
 @kotlin.internal.InlineOnly
 public actual inline fun String.toUpperCase(): String = asDynamic().toUpperCase()
 
@@ -190,6 +192,8 @@ public actual inline fun String.uppercase(): String = asDynamic().toUpperCase()
 /**
  * Returns a copy of this string converted to lower case using the rules of the default locale.
  */
+@Deprecated("Use lowercase() instead.", ReplaceWith("lowercase()"))
+@DeprecatedSinceKotlin(warningSince = "1.5")
 @kotlin.internal.InlineOnly
 public actual inline fun String.toLowerCase(): String = asDynamic().toLowerCase()
 

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

@@ -83,6 +83,8 @@ public actual fun CharSequence.regionMatches(thisOffset: Int, other: CharSequenc
  *
  * @sample samples.text.Strings.capitalize
  */
+@Deprecated("Use replaceFirstChar instead.", ReplaceWith("replaceFirstChar { if (it.isLowerCase()) it.titlecase() else it.toString() }"))
+@DeprecatedSinceKotlin(warningSince = "1.5")
 public actual fun String.capitalize(): String {
     return if (isNotEmpty()) substring(0, 1).toUpperCase() + substring(1) else this
 }
@@ -93,6 +95,8 @@ public actual fun String.capitalize(): String {
  *
  * @sample samples.text.Strings.decapitalize
  */
+@Deprecated("Use replaceFirstChar instead.", ReplaceWith("replaceFirstChar { it.lowercase() }"))
+@DeprecatedSinceKotlin(warningSince = "1.5")
 public actual fun String.decapitalize(): String {
     return if (isNotEmpty()) substring(0, 1).toLowerCase() + substring(1) else this
 }