From ef1abc3b975e1c77fc8663c5e5e95769fc934551 Mon Sep 17 00:00:00 2001
From: Robert Jaros <rjaros@finn.pl>
Date: Wed, 20 May 2020 17:12:56 +0200
Subject: Make all stateful components implement ObservableState interface

---
 .../pl/treksoft/kvision/form/time/DateTime.kt      |  9 +++++++-
 .../pl/treksoft/kvision/form/time/DateTimeInput.kt | 11 ++++++++-
 .../treksoft/kvision/form/select/SelectRemote.kt   |  9 +++++++-
 .../pl/treksoft/kvision/form/select/Select.kt      |  9 +++++++-
 .../pl/treksoft/kvision/form/select/SelectInput.kt | 17 ++++++++++++--
 .../pl/treksoft/kvision/form/spinner/Spinner.kt    |  9 +++++++-
 .../treksoft/kvision/form/spinner/SpinnerInput.kt  | 17 ++++++++++++--
 .../main/kotlin/pl/treksoft/kvision/react/React.kt | 16 ++++++++++++-
 src/main/kotlin/pl/treksoft/kvision/core/Widget.kt |  2 +-
 .../pl/treksoft/kvision/form/check/CheckBox.kt     | 15 ++++++++++++-
 .../pl/treksoft/kvision/form/check/CheckInput.kt   | 24 ++++++++++++++++++--
 .../kotlin/pl/treksoft/kvision/form/check/Radio.kt |  9 +++++++-
 .../pl/treksoft/kvision/form/check/RadioGroup.kt   | 19 ++++++++++++++--
 .../treksoft/kvision/form/check/RadioGroupInput.kt | 17 ++++++++++++--
 .../kotlin/pl/treksoft/kvision/form/range/Range.kt |  9 +++++++-
 .../pl/treksoft/kvision/form/range/RangeInput.kt   | 17 ++++++++++++--
 .../treksoft/kvision/form/select/SimpleSelect.kt   |  9 +++++++-
 .../kvision/form/select/SimpleSelectInput.kt       | 17 ++++++++++++--
 .../pl/treksoft/kvision/form/text/AbstractText.kt  | 10 ++++++++-
 .../kvision/form/text/AbstractTextInput.kt         | 26 ++++++++++++++++++++--
 .../pl/treksoft/kvision/state/StateBinding.kt      |  2 +-
 21 files changed, 244 insertions(+), 29 deletions(-)

diff --git a/kvision-modules/kvision-bootstrap-datetime/src/main/kotlin/pl/treksoft/kvision/form/time/DateTime.kt b/kvision-modules/kvision-bootstrap-datetime/src/main/kotlin/pl/treksoft/kvision/form/time/DateTime.kt
index 68ec96a2..115781cd 100644
--- a/kvision-modules/kvision-bootstrap-datetime/src/main/kotlin/pl/treksoft/kvision/form/time/DateTime.kt
+++ b/kvision-modules/kvision-bootstrap-datetime/src/main/kotlin/pl/treksoft/kvision/form/time/DateTime.kt
@@ -28,6 +28,7 @@ import pl.treksoft.kvision.form.DateFormControl
 import pl.treksoft.kvision.form.FieldLabel
 import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 import kotlin.js.Date
 
@@ -44,7 +45,7 @@ import kotlin.js.Date
 open class DateTime(
     value: Date? = null, name: String? = null, format: String = "YYYY-MM-DD HH:mm", label: String? = null,
     rich: Boolean = false
-) : SimplePanel(setOf("form-group")), DateFormControl {
+) : SimplePanel(setOf("form-group")), DateFormControl, ObservableState<Date?> {
 
     /**
      * Date/time input value.
@@ -264,6 +265,12 @@ open class DateTime(
         input.blur()
     }
 
+    override fun getState(): Date? = input.getState()
+
+    override fun subscribe(observer: (Date?) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/kvision-modules/kvision-bootstrap-datetime/src/main/kotlin/pl/treksoft/kvision/form/time/DateTimeInput.kt b/kvision-modules/kvision-bootstrap-datetime/src/main/kotlin/pl/treksoft/kvision/form/time/DateTimeInput.kt
index 967ca9db..d870947b 100644
--- a/kvision-modules/kvision-bootstrap-datetime/src/main/kotlin/pl/treksoft/kvision/form/time/DateTimeInput.kt
+++ b/kvision-modules/kvision-bootstrap-datetime/src/main/kotlin/pl/treksoft/kvision/form/time/DateTimeInput.kt
@@ -33,6 +33,7 @@ import pl.treksoft.kvision.html.icon
 import pl.treksoft.kvision.html.span
 import pl.treksoft.kvision.i18n.I18n
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.types.toDateF
 import pl.treksoft.kvision.types.toStringF
 import pl.treksoft.kvision.utils.obj
@@ -53,7 +54,7 @@ internal const val DEFAULT_STEPPING = 5
 open class DateTimeInput(
     value: Date? = null, format: String = "YYYY-MM-DD HH:mm",
     classes: Set<String> = setOf()
-) : SimplePanel(classes + "input-group" + "date"), FormInput {
+) : SimplePanel(classes + "input-group" + "date"), FormInput, ObservableState<Date?> {
 
     private var initialized = false
 
@@ -404,6 +405,14 @@ open class DateTimeInput(
     override fun blur() {
         input.blur()
     }
+
+    override fun getState(): Date? = input.getState()?.toDateF(format)
+
+    override fun subscribe(observer: (Date?) -> Unit): () -> Unit {
+        return input.subscribe { str ->
+            observer(str?.toDateF(format))
+        }
+    }
 }
 
 /**
diff --git a/kvision-modules/kvision-bootstrap-select-remote/src/main/kotlin/pl/treksoft/kvision/form/select/SelectRemote.kt b/kvision-modules/kvision-bootstrap-select-remote/src/main/kotlin/pl/treksoft/kvision/form/select/SelectRemote.kt
index b4e4738c..18c522d5 100644
--- a/kvision-modules/kvision-bootstrap-select-remote/src/main/kotlin/pl/treksoft/kvision/form/select/SelectRemote.kt
+++ b/kvision-modules/kvision-bootstrap-select-remote/src/main/kotlin/pl/treksoft/kvision/form/select/SelectRemote.kt
@@ -31,6 +31,7 @@ import pl.treksoft.kvision.form.StringFormControl
 import pl.treksoft.kvision.panel.SimplePanel
 import pl.treksoft.kvision.remote.KVServiceManager
 import pl.treksoft.kvision.remote.RemoteOption
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 
 /**
@@ -60,7 +61,7 @@ open class SelectRemote<T : Any>(
     preload: Boolean = false,
     label: String? = null,
     rich: Boolean = false
-) : SimplePanel(setOf("form-group")), StringFormControl {
+) : SimplePanel(setOf("form-group")), StringFormControl, ObservableState<String?> {
     /**
      * A value of the selected option.
      */
@@ -254,6 +255,12 @@ open class SelectRemote<T : Any>(
         input.blur()
     }
 
+    override fun getState(): String? = input.getState()
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/kvision-modules/kvision-bootstrap-select/src/main/kotlin/pl/treksoft/kvision/form/select/Select.kt b/kvision-modules/kvision-bootstrap-select/src/main/kotlin/pl/treksoft/kvision/form/select/Select.kt
index 4ffece7d..5fb92ab8 100644
--- a/kvision-modules/kvision-bootstrap-select/src/main/kotlin/pl/treksoft/kvision/form/select/Select.kt
+++ b/kvision-modules/kvision-bootstrap-select/src/main/kotlin/pl/treksoft/kvision/form/select/Select.kt
@@ -30,6 +30,7 @@ import pl.treksoft.kvision.form.FieldLabel
 import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.form.StringFormControl
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 
 /**
@@ -52,7 +53,7 @@ open class Select(
     options: List<StringPair>? = null, value: String? = null, name: String? = null,
     multiple: Boolean = false, ajaxOptions: AjaxOptions? = null, label: String? = null,
     rich: Boolean = false
-) : SimplePanel(setOf("form-group")), StringFormControl {
+) : SimplePanel(setOf("form-group")), StringFormControl, ObservableState<String?> {
 
     /**
      * A list of options (value to label pairs) for the select control.
@@ -272,6 +273,12 @@ open class Select(
         input.blur()
     }
 
+    override fun getState(): String? = input.getState()
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/kvision-modules/kvision-bootstrap-select/src/main/kotlin/pl/treksoft/kvision/form/select/SelectInput.kt b/kvision-modules/kvision-bootstrap-select/src/main/kotlin/pl/treksoft/kvision/form/select/SelectInput.kt
index ced0945d..5cba791c 100644
--- a/kvision-modules/kvision-bootstrap-select/src/main/kotlin/pl/treksoft/kvision/form/select/SelectInput.kt
+++ b/kvision-modules/kvision-bootstrap-select/src/main/kotlin/pl/treksoft/kvision/form/select/SelectInput.kt
@@ -33,6 +33,7 @@ import pl.treksoft.kvision.form.InputSize
 import pl.treksoft.kvision.form.ValidationStatus
 import pl.treksoft.kvision.html.ButtonStyle
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.asString
 import pl.treksoft.kvision.utils.obj
 import pl.treksoft.kvision.utils.set
@@ -72,7 +73,9 @@ open class SelectInput(
     options: List<StringPair>? = null, value: String? = null,
     multiple: Boolean = false, ajaxOptions: AjaxOptions? = null,
     classes: Set<String> = setOf()
-) : SimplePanel(classes), FormInput {
+) : SimplePanel(classes), FormInput, ObservableState<String?> {
+
+    protected val observers = mutableListOf<(String?) -> Unit>()
 
     /**
      * A list of options (value to label pairs) for the select control.
@@ -82,7 +85,7 @@ open class SelectInput(
     /**
      * A value of the selected option.
      */
-    var value by refreshOnUpdate(value) { refreshState() }
+    var value by refreshOnUpdate(value) { refreshState(); observers.forEach { ob -> ob(it) } }
 
     /**
      * The name attribute of the generated HTML select element.
@@ -396,6 +399,16 @@ open class SelectInput(
     override fun blur() {
         getElementJQuery()?.blur()
     }
+
+    override fun getState(): String? = value
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        observers += observer
+        observer(value)
+        return {
+            observers -= observer
+        }
+    }
 }
 
 /**
diff --git a/kvision-modules/kvision-bootstrap-spinner/src/main/kotlin/pl/treksoft/kvision/form/spinner/Spinner.kt b/kvision-modules/kvision-bootstrap-spinner/src/main/kotlin/pl/treksoft/kvision/form/spinner/Spinner.kt
index 3901cc4f..2dbcd443 100644
--- a/kvision-modules/kvision-bootstrap-spinner/src/main/kotlin/pl/treksoft/kvision/form/spinner/Spinner.kt
+++ b/kvision-modules/kvision-bootstrap-spinner/src/main/kotlin/pl/treksoft/kvision/form/spinner/Spinner.kt
@@ -30,6 +30,7 @@ import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.form.NumberFormControl
 import pl.treksoft.kvision.html.ButtonStyle
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 
 /**
@@ -52,7 +53,7 @@ open class Spinner(
     decimals: Int = 0, val buttonsType: ButtonsType = ButtonsType.VERTICAL,
     forceType: ForceType = ForceType.NONE, buttonStyle: ButtonStyle? = null, label: String? = null,
     rich: Boolean = false
-) : SimplePanel(setOf("form-group")), NumberFormControl {
+) : SimplePanel(setOf("form-group")), NumberFormControl, ObservableState<Number?> {
 
     /**
      * Spinner value.
@@ -252,6 +253,12 @@ open class Spinner(
         invalidFeedback.addCssClass("col-sm-${horizontalRatio.fields}")
     }
 
+    override fun getState(): Number? = input.getState()
+
+    override fun subscribe(observer: (Number?) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/kvision-modules/kvision-bootstrap-spinner/src/main/kotlin/pl/treksoft/kvision/form/spinner/SpinnerInput.kt b/kvision-modules/kvision-bootstrap-spinner/src/main/kotlin/pl/treksoft/kvision/form/spinner/SpinnerInput.kt
index 98b7be62..9ed9d707 100644
--- a/kvision-modules/kvision-bootstrap-spinner/src/main/kotlin/pl/treksoft/kvision/form/spinner/SpinnerInput.kt
+++ b/kvision-modules/kvision-bootstrap-spinner/src/main/kotlin/pl/treksoft/kvision/form/spinner/SpinnerInput.kt
@@ -31,6 +31,7 @@ import pl.treksoft.kvision.form.FormInput
 import pl.treksoft.kvision.form.InputSize
 import pl.treksoft.kvision.form.ValidationStatus
 import pl.treksoft.kvision.html.ButtonStyle
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.obj
 import pl.treksoft.kvision.utils.set
 
@@ -75,12 +76,14 @@ open class SpinnerInput(
     decimals: Int = 0, val buttonsType: ButtonsType = ButtonsType.VERTICAL,
     forceType: ForceType = ForceType.NONE, buttonStyle: ButtonStyle? = null,
     classes: Set<String> = setOf()
-) : Widget(classes + "form-control"), FormInput {
+) : Widget(classes + "form-control"), FormInput, ObservableState<Number?> {
+
+    protected val observers = mutableListOf<(Number?) -> Unit>()
 
     /**
      * Spinner value.
      */
-    var value by refreshOnUpdate(value) { refreshState() }
+    var value by refreshOnUpdate(value) { refreshState(); observers.forEach { ob -> ob(it) } }
 
     /**
      * The value attribute of the generated HTML input element.
@@ -328,6 +331,16 @@ open class SpinnerInput(
     override fun blur() {
         getElementJQuery()?.blur()
     }
+
+    override fun getState(): Number? = value
+
+    override fun subscribe(observer: (Number?) -> Unit): () -> Unit {
+        observers += observer
+        observer(value)
+        return {
+            observers -= observer
+        }
+    }
 }
 
 /**
diff --git a/kvision-modules/kvision-react/src/main/kotlin/pl/treksoft/kvision/react/React.kt b/kvision-modules/kvision-react/src/main/kotlin/pl/treksoft/kvision/react/React.kt
index 7424159f..79f4d1a0 100644
--- a/kvision-modules/kvision-react/src/main/kotlin/pl/treksoft/kvision/react/React.kt
+++ b/kvision-modules/kvision-react/src/main/kotlin/pl/treksoft/kvision/react/React.kt
@@ -27,6 +27,7 @@ import org.w3c.dom.HTMLElement
 import pl.treksoft.kvision.KVManagerReact
 import pl.treksoft.kvision.core.Container
 import pl.treksoft.kvision.core.Widget
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.set
 import react.RBuilder
 import react.dom.render as ReactRender
@@ -41,12 +42,15 @@ class React<S>(
     state: S,
     classes: Set<String> = setOf(),
     private val builder: RBuilder.(getState: () -> S, changeState: ((S) -> S) -> Unit) -> Unit
-) : Widget(classes) {
+) : Widget(classes), ObservableState<S> {
+
+    private val observers = mutableListOf<(S) -> Unit>()
 
     var state = state
         set(value) {
             field = value
             refreshFunction?.invoke()
+            observers.forEach { it(state) }
         }
 
     private var refreshFunction: (() -> Unit)? = null
@@ -76,6 +80,16 @@ class React<S>(
             KVManagerReact.reactDom.unmountComponentAtNode(it)
         }
     }
+
+    override fun getState(): S = state
+
+    override fun subscribe(observer: (S) -> Unit): () -> Unit {
+        observers += observer
+        observer(state)
+        return {
+            observers -= observer
+        }
+    }
 }
 
 /**
diff --git a/src/main/kotlin/pl/treksoft/kvision/core/Widget.kt b/src/main/kotlin/pl/treksoft/kvision/core/Widget.kt
index ba4db0cc..b28943dd 100644
--- a/src/main/kotlin/pl/treksoft/kvision/core/Widget.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/core/Widget.kt
@@ -1017,7 +1017,7 @@ open class Widget(classes: Set<String> = setOf()) : StyledComponent(), Component
          * An extension function which binds the widget to the observable state.
          * Used by [pl.treksoft.kvision.state.bind]
          */
-        internal fun <S : Any, W : Widget> W.bindState(
+        internal fun <S, W : Widget> W.bindState(
             observableState: ObservableState<S>,
             factory: (W.(S) -> Unit)
         ): W {
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/check/CheckBox.kt b/src/main/kotlin/pl/treksoft/kvision/form/check/CheckBox.kt
index 60147114..370f5ab1 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/check/CheckBox.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/check/CheckBox.kt
@@ -30,6 +30,7 @@ import pl.treksoft.kvision.form.FieldLabel
 import pl.treksoft.kvision.form.FormHorizontalRatio
 import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 
 /**
@@ -55,7 +56,7 @@ enum class CheckBoxStyle(internal val className: String) {
 open class CheckBox(
     value: Boolean = false, name: String? = null, label: String? = null,
     rich: Boolean = false
-) : SimplePanel(setOf("form-check", "abc-checkbox")), BoolFormControl {
+) : SimplePanel(setOf("form-check", "abc-checkbox")), BoolFormControl, ObservableState<Boolean> {
 
     /**
      * The selection state of the checkbox.
@@ -65,6 +66,7 @@ open class CheckBox(
         set(value) {
             input.value = value
         }
+
     /**
      * The value attribute of the generated HTML input element.
      *
@@ -76,6 +78,7 @@ open class CheckBox(
         set(value) {
             input.startValue = value
         }
+
     /**
      * The label text bound to the input element.
      */
@@ -84,6 +87,7 @@ open class CheckBox(
         set(value) {
             flabel.content = value
         }
+
     /**
      * Determines if [label] can contain HTML code.
      */
@@ -92,14 +96,17 @@ open class CheckBox(
         set(value) {
             flabel.rich = value
         }
+
     /**
      * The style (one of Bootstrap standard colors) of the input.
      */
     var style: CheckBoxStyle? by refreshOnUpdate()
+
     /**
      * Determines if the checkbox is rendered as a circle.
      */
     var circled by refreshOnUpdate(false)
+
     /**
      * Determines if the checkbox is rendered inline.
      */
@@ -189,6 +196,12 @@ open class CheckBox(
         addCssClass("form-group")
     }
 
+    override fun getState(): Boolean = input.getState()
+
+    override fun subscribe(observer: (Boolean) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/check/CheckInput.kt b/src/main/kotlin/pl/treksoft/kvision/form/check/CheckInput.kt
index f93fd436..70d57c51 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/check/CheckInput.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/check/CheckInput.kt
@@ -29,6 +29,7 @@ import pl.treksoft.kvision.core.Widget
 import pl.treksoft.kvision.form.FormInput
 import pl.treksoft.kvision.form.InputSize
 import pl.treksoft.kvision.form.ValidationStatus
+import pl.treksoft.kvision.state.ObservableState
 
 /**
  * Type of the check input control (checkbox or radio).
@@ -49,7 +50,9 @@ enum class CheckInputType(internal val type: String) {
 abstract class CheckInput(
     type: CheckInputType = CheckInputType.CHECKBOX, value: Boolean = false,
     classes: Set<String> = setOf()
-) : Widget(classes), FormInput {
+) : Widget(classes), FormInput, ObservableState<Boolean> {
+
+    protected val observers = mutableListOf<(Boolean) -> Unit>()
 
     init {
         this.setInternalEventListener<CheckInput> {
@@ -67,7 +70,8 @@ abstract class CheckInput(
     /**
      * The selection state of the input.
      */
-    var value by refreshOnUpdate(value) { refreshState() }
+    var value by refreshOnUpdate(value) { refreshState(); observers.forEach { ob -> ob(it) } }
+
     /**
      * The value attribute of the generated HTML input element.
      *
@@ -75,26 +79,32 @@ abstract class CheckInput(
      * bound to the input selection state.
      */
     var startValue by refreshOnUpdate(value) { this.value = it; refresh() }
+
     /**
      * The type of the generated HTML input element.
      */
     var type by refreshOnUpdate(type)
+
     /**
      * The name attribute of the generated HTML input element.
      */
     override var name: String? by refreshOnUpdate()
+
     /**
      * Determines if the field is disabled.
      */
     override var disabled by refreshOnUpdate(false)
+
     /**
      * The additional String value used for the radio button group.
      */
     var extraValue: String? by refreshOnUpdate()
+
     /**
      * The size of the input.
      */
     override var size: InputSize? by refreshOnUpdate()
+
     /**
      * The validation status of the input.
      */
@@ -169,4 +179,14 @@ abstract class CheckInput(
     override fun blur() {
         getElementJQuery()?.blur()
     }
+
+    override fun getState(): Boolean = value
+
+    override fun subscribe(observer: (Boolean) -> Unit): () -> Unit {
+        observers += observer
+        observer(value)
+        return {
+            observers -= observer
+        }
+    }
 }
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/check/Radio.kt b/src/main/kotlin/pl/treksoft/kvision/form/check/Radio.kt
index b8757da2..03ae8595 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/check/Radio.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/check/Radio.kt
@@ -30,6 +30,7 @@ import pl.treksoft.kvision.form.FieldLabel
 import pl.treksoft.kvision.form.FormHorizontalRatio
 import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 
 /**
@@ -56,7 +57,7 @@ enum class RadioStyle(internal val className: String) {
 open class Radio(
     value: Boolean = false, extraValue: String? = null, name: String? = null, label: String? = null,
     rich: Boolean = false
-) : SimplePanel(classes = setOf("form-check")), BoolFormControl {
+) : SimplePanel(classes = setOf("form-check")), BoolFormControl, ObservableState<Boolean> {
 
     /**
      * The selection state of the radio button.
@@ -204,6 +205,12 @@ open class Radio(
         addCssClass("form-group")
     }
 
+    override fun getState(): Boolean = input.getState()
+
+    override fun subscribe(observer: (Boolean) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/check/RadioGroup.kt b/src/main/kotlin/pl/treksoft/kvision/form/check/RadioGroup.kt
index 234f5327..6433d708 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/check/RadioGroup.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/check/RadioGroup.kt
@@ -31,6 +31,7 @@ import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.form.StringFormControl
 import pl.treksoft.kvision.form.ValidationStatus
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 
 /**
  * The form field component rendered as a group of HTML *input type="radio"* elements with the same name attribute.
@@ -51,7 +52,9 @@ open class RadioGroup(
     options: List<StringPair>? = null, value: String? = null, name: String? = null, inline: Boolean = false,
     label: String? = null,
     rich: Boolean = false
-) : SimplePanel(setOf("form-group")), StringFormControl {
+) : SimplePanel(setOf("form-group")), StringFormControl, ObservableState<String?> {
+
+    protected val observers = mutableListOf<(String?) -> Unit>()
 
     /**
      * A list of options (label to value pairs) for the group.
@@ -61,7 +64,7 @@ open class RadioGroup(
     /**
      * A value of the selected option.
      */
-    override var value by refreshOnUpdate(value) { setValueToChildren(it) }
+    override var value by refreshOnUpdate(value) { setValueToChildren(it); observers.forEach { ob -> ob(it) } }
 
     /**
      * Determines if the options are rendered inline.
@@ -73,6 +76,7 @@ open class RadioGroup(
         set(value) {
             setDisabledToChildren(value)
         }
+
     /**
      * The label text of the options group.
      */
@@ -81,6 +85,7 @@ open class RadioGroup(
         set(value) {
             flabel.content = value
         }
+
     /**
      * Determines if [label] can contain HTML code.
      */
@@ -226,6 +231,16 @@ open class RadioGroup(
         invalidFeedback.addCssClass("col-sm-${horizontalRatio.fields}")
     }
 
+    override fun getState(): String? = value
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        observers += observer
+        observer(value)
+        return {
+            observers -= observer
+        }
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/check/RadioGroupInput.kt b/src/main/kotlin/pl/treksoft/kvision/form/check/RadioGroupInput.kt
index 5a47c3ce..3e9f0def 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/check/RadioGroupInput.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/check/RadioGroupInput.kt
@@ -28,6 +28,7 @@ import pl.treksoft.kvision.form.FormInput
 import pl.treksoft.kvision.form.InputSize
 import pl.treksoft.kvision.form.ValidationStatus
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 
 /**
  * The input component rendered as a group of HTML *input type="radio"* elements with the same name attribute.
@@ -44,7 +45,9 @@ import pl.treksoft.kvision.panel.SimplePanel
 @Suppress("TooManyFunctions")
 open class RadioGroupInput(
     options: List<StringPair>? = null, value: String? = null, name: String? = null, inline: Boolean = false
-) : SimplePanel(setOf("form-group")), FormInput {
+) : SimplePanel(setOf("form-group")), FormInput, ObservableState<String?> {
+
+    protected val observers = mutableListOf<(String?) -> Unit>()
 
     /**
      * A list of options (label to value pairs) for the group.
@@ -54,7 +57,7 @@ open class RadioGroupInput(
     /**
      * A value of the selected option.
      */
-    var value by refreshOnUpdate(value) { setValueToChildren(it) }
+    var value by refreshOnUpdate(value) { setValueToChildren(it); observers.forEach { ob -> ob(it) } }
 
     /**
      * Determines if the options are rendered inline.
@@ -172,6 +175,16 @@ open class RadioGroupInput(
         getChildren().filterIsInstance<Radio>().firstOrNull()?.blur()
     }
 
+    override fun getState(): String? = value
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        observers += observer
+        observer(value)
+        return {
+            observers -= observer
+        }
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/range/Range.kt b/src/main/kotlin/pl/treksoft/kvision/form/range/Range.kt
index dc8e57a0..d5acae8b 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/range/Range.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/range/Range.kt
@@ -29,6 +29,7 @@ import pl.treksoft.kvision.form.FormHorizontalRatio
 import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.form.NumberFormControl
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 
 /**
@@ -46,7 +47,7 @@ import pl.treksoft.kvision.utils.SnOn
 open class Range(
     value: Number? = null, name: String? = null, min: Number = 0, max: Number = 100, step: Number = DEFAULT_STEP,
     label: String? = null, rich: Boolean = false
-) : SimplePanel(setOf("form-group")), NumberFormControl {
+) : SimplePanel(setOf("form-group")), NumberFormControl, ObservableState<Number?> {
 
     /**
      * Range input value.
@@ -212,6 +213,12 @@ open class Range(
         invalidFeedback.addCssClass("col-sm-${horizontalRatio.fields}")
     }
 
+    override fun getState(): Number? = input.getState()
+
+    override fun subscribe(observer: (Number?) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/range/RangeInput.kt b/src/main/kotlin/pl/treksoft/kvision/form/range/RangeInput.kt
index 4649c654..6112022d 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/range/RangeInput.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/range/RangeInput.kt
@@ -30,6 +30,7 @@ import pl.treksoft.kvision.core.Widget
 import pl.treksoft.kvision.form.FormInput
 import pl.treksoft.kvision.form.InputSize
 import pl.treksoft.kvision.form.ValidationStatus
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.set
 
 internal const val DEFAULT_STEP = 1
@@ -47,12 +48,14 @@ internal const val DEFAULT_STEP = 1
 open class RangeInput(
     value: Number? = null, min: Number = 0, max: Number = 100, step: Number = DEFAULT_STEP,
     classes: Set<String> = setOf()
-) : Widget(classes + "form-control-range"), FormInput {
+) : Widget(classes + "form-control-range"), FormInput, ObservableState<Number?> {
+
+    protected val observers = mutableListOf<(Number?) -> Unit>()
 
     /**
      * Range input value.
      */
-    var value by refreshOnUpdate(value ?: (min as Number?)) { refreshState() }
+    var value by refreshOnUpdate(value ?: (min as Number?)) { refreshState(); observers.forEach { ob -> ob(it) } }
 
     /**
      * The value attribute of the generated HTML input element.
@@ -223,6 +226,16 @@ open class RangeInput(
     override fun blur() {
         getElementJQuery()?.blur()
     }
+
+    override fun getState(): Number? = value
+
+    override fun subscribe(observer: (Number?) -> Unit): () -> Unit {
+        observers += observer
+        observer(value)
+        return {
+            observers -= observer
+        }
+    }
 }
 
 /**
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/select/SimpleSelect.kt b/src/main/kotlin/pl/treksoft/kvision/form/select/SimpleSelect.kt
index e797e050..043e8a02 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/select/SimpleSelect.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/select/SimpleSelect.kt
@@ -30,6 +30,7 @@ import pl.treksoft.kvision.form.FieldLabel
 import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.form.StringFormControl
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 
 /**
@@ -47,7 +48,7 @@ import pl.treksoft.kvision.utils.SnOn
 open class SimpleSelect(
     options: List<StringPair>? = null, value: String? = null, emptyOption: Boolean = false,
     name: String? = null, label: String? = null, rich: Boolean = false
-) : SimplePanel(setOf("form-group")), StringFormControl {
+) : SimplePanel(setOf("form-group")), StringFormControl, ObservableState<String?> {
 
     /**
      * A list of options (value to label pairs) for the select control.
@@ -183,6 +184,12 @@ open class SimpleSelect(
         input.blur()
     }
 
+    override fun getState(): String? = input.getState()
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
     companion object {
         internal var counter = 0
     }
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/select/SimpleSelectInput.kt b/src/main/kotlin/pl/treksoft/kvision/form/select/SimpleSelectInput.kt
index 63eb98b5..dd567cad 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/select/SimpleSelectInput.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/select/SimpleSelectInput.kt
@@ -31,6 +31,7 @@ import pl.treksoft.kvision.form.ValidationStatus
 import pl.treksoft.kvision.html.TAG
 import pl.treksoft.kvision.html.Tag
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.set
 
 internal const val KVNULL = "#kvnull"
@@ -47,7 +48,9 @@ internal const val KVNULL = "#kvnull"
 open class SimpleSelectInput(
     options: List<StringPair>? = null, value: String? = null, emptyOption: Boolean = false,
     classes: Set<String> = setOf()
-) : SimplePanel(classes + "form-control"), FormInput {
+) : SimplePanel(classes + "form-control"), FormInput, ObservableState<String?> {
+
+    protected val observers = mutableListOf<(String?) -> Unit>()
 
     /**
      * A list of options (value to label pairs) for the select control.
@@ -57,7 +60,7 @@ open class SimpleSelectInput(
     /**
      * Text input value.
      */
-    var value by refreshOnUpdate(value) { refreshState() }
+    var value by refreshOnUpdate(value) { refreshState(); observers.forEach { ob -> ob(it) } }
 
     /**
      * The value of the selected child option.
@@ -207,6 +210,16 @@ open class SimpleSelectInput(
     override fun blur() {
         getElementJQuery()?.blur()
     }
+
+    override fun getState(): String? = value
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        observers += observer
+        observer(value)
+        return {
+            observers -= observer
+        }
+    }
 }
 
 /**
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/text/AbstractText.kt b/src/main/kotlin/pl/treksoft/kvision/form/text/AbstractText.kt
index 8a5acf8b..9ac2a636 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/text/AbstractText.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/text/AbstractText.kt
@@ -27,6 +27,7 @@ import pl.treksoft.kvision.form.FieldLabel
 import pl.treksoft.kvision.form.InvalidFeedback
 import pl.treksoft.kvision.form.StringFormControl
 import pl.treksoft.kvision.panel.SimplePanel
+import pl.treksoft.kvision.state.ObservableState
 import pl.treksoft.kvision.utils.SnOn
 
 /**
@@ -37,7 +38,7 @@ import pl.treksoft.kvision.utils.SnOn
  * @param rich determines if [label] can contain HTML code
  */
 abstract class AbstractText(label: String? = null, rich: Boolean = false) :
-    SimplePanel(setOf("form-group")), StringFormControl {
+    SimplePanel(setOf("form-group")), StringFormControl, ObservableState<String?> {
 
     /**
      * Text input value.
@@ -155,4 +156,11 @@ abstract class AbstractText(label: String? = null, rich: Boolean = false) :
     override fun blur() {
         input.blur()
     }
+
+    override fun getState(): String? = input.getState()
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        return input.subscribe(observer)
+    }
+
 }
diff --git a/src/main/kotlin/pl/treksoft/kvision/form/text/AbstractTextInput.kt b/src/main/kotlin/pl/treksoft/kvision/form/text/AbstractTextInput.kt
index 192b33c8..98bd5f1a 100644
--- a/src/main/kotlin/pl/treksoft/kvision/form/text/AbstractTextInput.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/form/text/AbstractTextInput.kt
@@ -28,6 +28,7 @@ import pl.treksoft.kvision.core.Widget
 import pl.treksoft.kvision.form.FormInput
 import pl.treksoft.kvision.form.InputSize
 import pl.treksoft.kvision.form.ValidationStatus
+import pl.treksoft.kvision.state.ObservableState
 
 /**
  * Base class for basic text components.
@@ -39,7 +40,9 @@ import pl.treksoft.kvision.form.ValidationStatus
 abstract class AbstractTextInput(
     value: String? = null,
     classes: Set<String> = setOf()
-) : Widget(classes), FormInput {
+) : Widget(classes), FormInput, ObservableState<String?> {
+
+    protected val observers = mutableListOf<(String?) -> Unit>()
 
     init {
         this.setInternalEventListener<AbstractTextInput> {
@@ -52,7 +55,8 @@ abstract class AbstractTextInput(
     /**
      * Text input value.
      */
-    var value by refreshOnUpdate(value) { refreshState() }
+    var value by refreshOnUpdate(value) { refreshState(); observers.forEach { ob -> ob(it) } }
+
     /**
      * The value attribute of the generated HTML input element.
      *
@@ -60,34 +64,42 @@ abstract class AbstractTextInput(
      * bound to the text input value.
      */
     var startValue by refreshOnUpdate(value) { this.value = it; refresh() }
+
     /**
      * The placeholder for the text input.
      */
     var placeholder: String? by refreshOnUpdate()
+
     /**
      * The name attribute of the generated HTML input element.
      */
     override var name: String? by refreshOnUpdate()
+
     /**
      * Maximal length of the text input value.
      */
     var maxlength: Int? by refreshOnUpdate()
+
     /**
      * Determines if the field is disabled.
      */
     override var disabled by refreshOnUpdate(false)
+
     /**
      * Determines if the text input is automatically focused.
      */
     var autofocus: Boolean? by refreshOnUpdate()
+
     /**
      * Determines if the text input is read-only.
      */
     var readonly: Boolean? by refreshOnUpdate()
+
     /**
      * The size of the input.
      */
     override var size: InputSize? by refreshOnUpdate()
+
     /**
      * The validation status of the input.
      */
@@ -174,4 +186,14 @@ abstract class AbstractTextInput(
     override fun blur() {
         getElementJQuery()?.blur()
     }
+
+    override fun getState(): String? = value
+
+    override fun subscribe(observer: (String?) -> Unit): () -> Unit {
+        observers += observer
+        observer(value)
+        return {
+            observers -= observer
+        }
+    }
 }
diff --git a/src/main/kotlin/pl/treksoft/kvision/state/StateBinding.kt b/src/main/kotlin/pl/treksoft/kvision/state/StateBinding.kt
index d330f76d..6c8090b7 100644
--- a/src/main/kotlin/pl/treksoft/kvision/state/StateBinding.kt
+++ b/src/main/kotlin/pl/treksoft/kvision/state/StateBinding.kt
@@ -15,7 +15,7 @@ import pl.treksoft.kvision.core.Widget.Companion.bindState
  * @param observableState the state
  * @param factory a function which re-creates the view based on the given state
  */
-fun <S : Any, W : Widget> W.bind(
+fun <S, W : Widget> W.bind(
     observableState: ObservableState<S>,
     factory: (W.(S) -> Unit)
 ): W {
-- 
cgit