add joinTo

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## 0.5.23
 
+* `Versions`
+* `Common`:
+    * New extensions `Iterable#joinTo` and `Array#joinTo`
+
 ## 0.5.22
 
 * `Versions`

common/src/commonMain/kotlin/dev/inmo/micro_utils/common/JoinTo.kt

@@ -0,0 +1,33 @@
+package dev.inmo.micro_utils.common
+
+inline fun <I, R> Iterable<I>.joinTo(
+    crossinline separatorFun: (I) -> R?,
+    prefix: R?,
+    postfix: R?,
+    crossinline transform: (I) -> R?
+): List<R> {
+    val result = mutableListOf<R>()
+    val iterator = iterator()
+
+    prefix ?.let(result::add)
+
+    while (iterator.hasNext()) {
+        val element = iterator.next()
+        result.add(transform(element) ?: continue)
+
+        if (iterator.hasNext()) {
+            result.add(separatorFun(element) ?: continue)
+        }
+    }
+
+    postfix ?.let(result::add)
+
+    return result
+}
+
+inline fun <I, reified R> Array<I>.joinTo(
+    crossinline separatorFun: (I) -> R?,
+    prefix: R?,
+    postfix: R?,
+    crossinline transform: (I) -> R?
+): Array<R> = asIterable().joinTo(separatorFun, prefix, postfix, transform).toTypedArray()