From 76cec0469ff8de4b4cc35136e38d097e483bbddb Mon Sep 17 00:00:00 2001
From: Alexander Nozik <altavir@gmail.com>
Date: Tue, 30 May 2023 20:23:43 +0300
Subject: [PATCH] add useProperty subscription

---
 .../controls/spec/DevicePropertySpec.kt       | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DevicePropertySpec.kt b/controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DevicePropertySpec.kt
index ce83edc..cf8c741 100644
--- a/controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DevicePropertySpec.kt
+++ b/controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DevicePropertySpec.kt
@@ -126,6 +126,25 @@ public fun <D : Device, T> D.onPropertyChange(
         }
     }.launchIn(this)
 
+/**
+ * Call [callback] on initial property value and each value change
+ */
+public fun <D : Device, T> D.useProperty(
+    spec: DevicePropertySpec<D, T>,
+    callback: suspend (T) -> Unit,
+): Job = launch {
+    callback(read(spec))
+    messageFlow
+        .filterIsInstance<PropertyChangedMessage>()
+        .filter { it.property == spec.name }
+        .collect { change ->
+            val newValue = spec.converter.metaToObject(change.value)
+            if (newValue != null) {
+                callback(newValue)
+            }
+        }
+}
+
 
 /**
  * Reset the logical state of a property