Merge pull request #2013 from JetBrains/KT-16305-MUTATION_OBSERVER_INIT

Skip assignment for null-value ArrayLike object in idl-based generate…

libraries/stdlib/js/src/org.w3c/org.w3c.dom.kt

@@ -805,6 +805,9 @@ public external abstract class MediaError {
     }
 }
 
+/**
+ * Exposes the JavaScript [AudioTrackList](https://developer.mozilla.org/en/docs/Web/API/AudioTrackList) to Kotlin
+ */
 public external abstract class AudioTrackList : EventTarget {
     open val length: Int
     open var onchange: ((Event) -> dynamic)?
@@ -814,6 +817,9 @@ public external abstract class AudioTrackList : EventTarget {
 }
 @kotlin.internal.InlineOnly inline operator fun AudioTrackList.get(index: Int): AudioTrack? = asDynamic()[index]
 
+/**
+ * Exposes the JavaScript [AudioTrack](https://developer.mozilla.org/en/docs/Web/API/AudioTrack) to Kotlin
+ */
 public external abstract class AudioTrack : UnionAudioTrackOrTextTrackOrVideoTrack {
     open val id: String
     open val kind: String
@@ -822,6 +828,9 @@ public external abstract class AudioTrack : UnionAudioTrackOrTextTrackOrVideoTra
     open var enabled: Boolean
 }
 
+/**
+ * Exposes the JavaScript [VideoTrackList](https://developer.mozilla.org/en/docs/Web/API/VideoTrackList) to Kotlin
+ */
 public external abstract class VideoTrackList : EventTarget {
     open val length: Int
     open val selectedIndex: Int
@@ -832,6 +841,9 @@ public external abstract class VideoTrackList : EventTarget {
 }
 @kotlin.internal.InlineOnly inline operator fun VideoTrackList.get(index: Int): VideoTrack? = asDynamic()[index]
 
+/**
+ * Exposes the JavaScript [VideoTrack](https://developer.mozilla.org/en/docs/Web/API/VideoTrack) to Kotlin
+ */
 public external abstract class VideoTrack : UnionAudioTrackOrTextTrackOrVideoTrack {
     open val id: String
     open val kind: String
@@ -872,6 +884,9 @@ public external abstract class TextTrackCueList {
 }
 @kotlin.internal.InlineOnly inline operator fun TextTrackCueList.get(index: Int): TextTrackCue? = asDynamic()[index]
 
+/**
+ * Exposes the JavaScript [TextTrackCue](https://developer.mozilla.org/en/docs/Web/API/TextTrackCue) to Kotlin
+ */
 public external abstract class TextTrackCue : EventTarget {
     open val track: TextTrack?
     open var id: String
@@ -891,6 +906,9 @@ public external abstract class TimeRanges {
     fun end(index: Int): Double
 }
 
+/**
+ * Exposes the JavaScript [TrackEvent](https://developer.mozilla.org/en/docs/Web/API/TrackEvent) to Kotlin
+ */
 public external open class TrackEvent(type: String, eventInitDict: TrackEventInit = definedExternally) : Event {
     open val track: UnionAudioTrackOrTextTrackOrVideoTrack?
 }
@@ -2398,7 +2416,9 @@ public inline fun MessageEventInit(data: Any? = null, origin: String? = "", last
     o["origin"] = origin
     o["lastEventId"] = lastEventId
     o["source"] = source
-    o["ports"] = ports
+    if (ports != null) {
+        o["ports"] = ports
+    }
     o["bubbles"] = bubbles
     o["cancelable"] = cancelable
     o["composed"] = composed
@@ -2726,6 +2746,9 @@ public external abstract class HTMLAppletElement : HTMLElement {
     open var width: String
 }
 
+/**
+ * Exposes the JavaScript [HTMLMarqueeElement](https://developer.mozilla.org/en/docs/Web/API/HTMLMarqueeElement) to Kotlin
+ */
 public external abstract class HTMLMarqueeElement : HTMLElement {
     open var behavior: String
     open var bgColor: String
@@ -2947,6 +2970,9 @@ public external open class MutationObserver(callback: (Array<MutationRecord>, Mu
     fun takeRecords(): Array<MutationRecord>
 }
 
+/**
+ * Exposes the JavaScript [MutationObserverInit](https://developer.mozilla.org/en/docs/Web/API/MutationObserverInit) to Kotlin
+ */
 public external interface MutationObserverInit {
     var childList: Boolean? /* = false */
         get() = definedExternally
@@ -2981,7 +3007,9 @@ public inline fun MutationObserverInit(childList: Boolean? = false, attributes:
     o["subtree"] = subtree
     o["attributeOldValue"] = attributeOldValue
     o["characterDataOldValue"] = characterDataOldValue
-    o["attributeFilter"] = attributeFilter
+    if (attributeFilter != null) {
+        o["attributeFilter"] = attributeFilter
+    }
 
     return o
 }
@@ -3459,6 +3487,9 @@ public external open class DOMPoint : DOMPointReadOnly {
     override var w: Double
 }
 
+/**
+ * Exposes the JavaScript [DOMPointInit](https://developer.mozilla.org/en/docs/Web/API/DOMPointInit) to Kotlin
+ */
 public external interface DOMPointInit {
     var x: Double? /* = 0.0 */
         get() = definedExternally
@@ -3662,6 +3693,9 @@ public inline fun ScrollOptions(behavior: ScrollBehavior? = ScrollBehavior.AUTO)
     return o
 }
 
+/**
+ * Exposes the JavaScript [ScrollToOptions](https://developer.mozilla.org/en/docs/Web/API/ScrollToOptions) to Kotlin
+ */
 public external interface ScrollToOptions : ScrollOptions {
     var left: Double?
         get() = definedExternally

libraries/stdlib/js/src/org.w3c/org.w3c.notifications.kt

@@ -130,7 +130,9 @@ public inline fun NotificationOptions(dir: NotificationDirection? = Notification
     o["requireInteraction"] = requireInteraction
     o["sticky"] = sticky
     o["data"] = data
-    o["actions"] = actions
+    if (actions != null) {
+        o["actions"] = actions
+    }
 
     return o
 }

libraries/stdlib/js/src/org.w3c/org.w3c.workers.kt

@@ -137,7 +137,9 @@ public inline fun ServiceWorkerMessageEventInit(data: Any? = null, origin: Strin
     o["origin"] = origin
     o["lastEventId"] = lastEventId
     o["source"] = source
-    o["ports"] = ports
+    if (ports != null) {
+        o["ports"] = ports
+    }
     o["bubbles"] = bubbles
     o["cancelable"] = cancelable
     o["composed"] = composed
@@ -235,8 +237,12 @@ public external interface ForeignFetchOptions {
 public inline fun ForeignFetchOptions(scopes: Array<String>?, origins: Array<String>?): ForeignFetchOptions {
     val o = js("({})")
 
-    o["scopes"] = scopes
+    if (scopes != null) {
-    o["origins"] = origins
+        o["scopes"] = scopes
+    }
+    if (origins != null) {
+        o["origins"] = origins
+    }
 
     return o
 }
@@ -323,7 +329,9 @@ public inline fun ForeignFetchResponse(response: Response?, origin: String? = nu
 
     o["response"] = response
     o["origin"] = origin
-    o["headers"] = headers
+    if (headers != null) {
+        o["headers"] = headers
+    }
 
     return o
 }
@@ -365,7 +373,9 @@ public inline fun ExtendableMessageEventInit(data: Any? = null, origin: String?
     o["origin"] = origin
     o["lastEventId"] = lastEventId
     o["source"] = source
-    o["ports"] = ports
+    if (ports != null) {
+        o["ports"] = ports
+    }
     o["bubbles"] = bubbles
     o["cancelable"] = cancelable
     o["composed"] = composed

libraries/tools/idl2k/src/main/kotlin/render.kt

@@ -304,7 +304,21 @@ fun Appendable.renderBuilderFunction(dictionary: GenerateTraitOrClass, allSuperT
 
     for (field in fields) {
         indent(level = 1)
-        appendln("o[\"${field.name}\"] = ${field.name.replaceKeywords()}")
+
+        val escapedFieldName = field.name.replaceKeywords()
+        val nullGuardedAssignment = field.type is ArrayType
+
+        if (nullGuardedAssignment) {
+            appendln("if ($escapedFieldName != null) {")
+            indent(level = 2)
+        }
+
+        appendln("o[\"${field.name}\"] = $escapedFieldName")
+
+        if (nullGuardedAssignment) {
+            indent(level = 1)
+            appendln("}")
+        }
     }
 
     appendln()