diff --git a/js/js.libraries/src/generated/org.khronos.webgl.kt b/js/js.libraries/src/generated/org.khronos.webgl.kt
index 45d1ae869fa..bf176325c77 100644
--- a/js/js.libraries/src/generated/org.khronos.webgl.kt
+++ b/js/js.libraries/src/generated/org.khronos.webgl.kt
@@ -20,15 +20,30 @@ import org.w3c.performance.*
 import org.w3c.workers.*
 import org.w3c.xhr.*
 
-native public open class WebGLContextAttributes {
-    var alpha: Boolean = true
-    var depth: Boolean = true
-    var stencil: Boolean = false
-    var antialias: Boolean = true
-    var premultipliedAlpha: Boolean = true
-    var preserveDrawingBuffer: Boolean = false
-    var preferLowPowerToHighPerformance: Boolean = false
-    var failIfMajorPerformanceCaveat: Boolean = false
+native public interface WebGLContextAttributes {
+    var alpha: Boolean
+    var depth: Boolean
+    var stencil: Boolean
+    var antialias: Boolean
+    var premultipliedAlpha: Boolean
+    var preserveDrawingBuffer: Boolean
+    var preferLowPowerToHighPerformance: Boolean
+    var failIfMajorPerformanceCaveat: Boolean
+}
+
+inline fun WebGLContextAttributes(alpha: Boolean = true, depth: Boolean = true, stencil: Boolean = false, antialias: Boolean = true, premultipliedAlpha: Boolean = true, preserveDrawingBuffer: Boolean = false, preferLowPowerToHighPerformance: Boolean = false, failIfMajorPerformanceCaveat: Boolean = false): WebGLContextAttributes {
+    val o = js("({})") as WebGLContextAttributes
+
+    o.`alpha` = alpha
+    o.`depth` = depth
+    o.`stencil` = stencil
+    o.`antialias` = antialias
+    o.`premultipliedAlpha` = premultipliedAlpha
+    o.`preserveDrawingBuffer` = preserveDrawingBuffer
+    o.`preferLowPowerToHighPerformance` = preferLowPowerToHighPerformance
+    o.`failIfMajorPerformanceCaveat` = failIfMajorPerformanceCaveat
+
+    return o
 }
 
 native public interface WebGLObject {
@@ -541,10 +556,20 @@ native public open class WebGLContextEvent(type: String, eventInit: WebGLContext
         get() = noImpl
 }
 
-native public open class WebGLContextEventInit : EventInit() {
+native public interface WebGLContextEventInit : EventInit {
     var statusMessage: String
 }
 
+inline fun WebGLContextEventInit(statusMessage: String, bubbles: Boolean = false, cancelable: Boolean = false): WebGLContextEventInit {
+    val o = js("({})") as WebGLContextEventInit
+
+    o.`statusMessage` = statusMessage
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public open class ArrayBuffer(length: Int) : Transferable {
     open val byteLength: Int
         get() = noImpl
diff --git a/js/js.libraries/src/generated/org.w3c.dom.events.kt b/js/js.libraries/src/generated/org.w3c.dom.events.kt
index 0094b17189f..7e6938fbdc6 100644
--- a/js/js.libraries/src/generated/org.w3c.dom.events.kt
+++ b/js/js.libraries/src/generated/org.w3c.dom.events.kt
@@ -121,9 +121,20 @@ native public open class UIEvent(type: String, eventInitDict: UIEventInit = noIm
     fun initUIEvent(typeArg: String, bubblesArg: Boolean, cancelableArg: Boolean, viewArg: Window?, detailArg: Int): Unit = noImpl
 }
 
-native public open class UIEventInit : EventInit() {
-    var view: Window? = null
-    var detail: Int = 0
+native public interface UIEventInit : EventInit {
+    var view: Window?
+    var detail: Int
+}
+
+inline fun UIEventInit(view: Window? = null, detail: Int = 0, bubbles: Boolean = false, cancelable: Boolean = false): UIEventInit {
+    val o = js("({})") as UIEventInit
+
+    o.`view` = view
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public open class FocusEvent(typeArg: String, focusEventInitDict: FocusEventInit = noImpl) : UIEvent(noImpl, noImpl) {
@@ -132,36 +143,107 @@ native public open class FocusEvent(typeArg: String, focusEventInitDict: FocusEv
     fun initFocusEvent(typeArg: String, bubblesArg: Boolean, cancelableArg: Boolean, viewArg: Window?, detailArg: Int, relatedTargetArg: EventTarget?): Unit = noImpl
 }
 
-native public open class FocusEventInit : UIEventInit() {
-    var relatedTarget: EventTarget? = null
+native public interface FocusEventInit : UIEventInit {
+    var relatedTarget: EventTarget?
 }
 
-native public open class MouseEventInit : EventModifierInit() {
-    var screenX: Int = 0
-    var screenY: Int = 0
-    var clientX: Int = 0
-    var clientY: Int = 0
-    var button: Short = 0
-    var buttons: Short = 0
-    var relatedTarget: EventTarget? = null
+inline fun FocusEventInit(relatedTarget: EventTarget? = null, view: Window? = null, detail: Int = 0, bubbles: Boolean = false, cancelable: Boolean = false): FocusEventInit {
+    val o = js("({})") as FocusEventInit
+
+    o.`relatedTarget` = relatedTarget
+    o.`view` = view
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
-native public open class EventModifierInit : UIEventInit() {
-    var ctrlKey: Boolean = false
-    var shiftKey: Boolean = false
-    var altKey: Boolean = false
-    var metaKey: Boolean = false
-    var modifierAltGraph: Boolean = false
-    var modifierCapsLock: Boolean = false
-    var modifierFn: Boolean = false
-    var modifierFnLock: Boolean = false
-    var modifierHyper: Boolean = false
-    var modifierNumLock: Boolean = false
-    var modifierOS: Boolean = false
-    var modifierScrollLock: Boolean = false
-    var modifierSuper: Boolean = false
-    var modifierSymbol: Boolean = false
-    var modifierSymbolLock: Boolean = false
+native public interface MouseEventInit : EventModifierInit {
+    var screenX: Int
+    var screenY: Int
+    var clientX: Int
+    var clientY: Int
+    var button: Short
+    var buttons: Short
+    var relatedTarget: EventTarget?
+}
+
+inline fun MouseEventInit(screenX: Int = 0, screenY: Int = 0, clientX: Int = 0, clientY: Int = 0, button: Short = 0, buttons: Short = 0, relatedTarget: EventTarget? = null, ctrlKey: Boolean = false, shiftKey: Boolean = false, altKey: Boolean = false, metaKey: Boolean = false, modifierAltGraph: Boolean = false, modifierCapsLock: Boolean = false, modifierFn: Boolean = false, modifierFnLock: Boolean = false, modifierHyper: Boolean = false, modifierNumLock: Boolean = false, modifierOS: Boolean = false, modifierScrollLock: Boolean = false, modifierSuper: Boolean = false, modifierSymbol: Boolean = false, modifierSymbolLock: Boolean = false, view: Window? = null, detail: Int = 0, bubbles: Boolean = false, cancelable: Boolean = false): MouseEventInit {
+    val o = js("({})") as MouseEventInit
+
+    o.`screenX` = screenX
+    o.`screenY` = screenY
+    o.`clientX` = clientX
+    o.`clientY` = clientY
+    o.`button` = button
+    o.`buttons` = buttons
+    o.`relatedTarget` = relatedTarget
+    o.`ctrlKey` = ctrlKey
+    o.`shiftKey` = shiftKey
+    o.`altKey` = altKey
+    o.`metaKey` = metaKey
+    o.`modifierAltGraph` = modifierAltGraph
+    o.`modifierCapsLock` = modifierCapsLock
+    o.`modifierFn` = modifierFn
+    o.`modifierFnLock` = modifierFnLock
+    o.`modifierHyper` = modifierHyper
+    o.`modifierNumLock` = modifierNumLock
+    o.`modifierOS` = modifierOS
+    o.`modifierScrollLock` = modifierScrollLock
+    o.`modifierSuper` = modifierSuper
+    o.`modifierSymbol` = modifierSymbol
+    o.`modifierSymbolLock` = modifierSymbolLock
+    o.`view` = view
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
+native public interface EventModifierInit : UIEventInit {
+    var ctrlKey: Boolean
+    var shiftKey: Boolean
+    var altKey: Boolean
+    var metaKey: Boolean
+    var modifierAltGraph: Boolean
+    var modifierCapsLock: Boolean
+    var modifierFn: Boolean
+    var modifierFnLock: Boolean
+    var modifierHyper: Boolean
+    var modifierNumLock: Boolean
+    var modifierOS: Boolean
+    var modifierScrollLock: Boolean
+    var modifierSuper: Boolean
+    var modifierSymbol: Boolean
+    var modifierSymbolLock: Boolean
+}
+
+inline fun EventModifierInit(ctrlKey: Boolean = false, shiftKey: Boolean = false, altKey: Boolean = false, metaKey: Boolean = false, modifierAltGraph: Boolean = false, modifierCapsLock: Boolean = false, modifierFn: Boolean = false, modifierFnLock: Boolean = false, modifierHyper: Boolean = false, modifierNumLock: Boolean = false, modifierOS: Boolean = false, modifierScrollLock: Boolean = false, modifierSuper: Boolean = false, modifierSymbol: Boolean = false, modifierSymbolLock: Boolean = false, view: Window? = null, detail: Int = 0, bubbles: Boolean = false, cancelable: Boolean = false): EventModifierInit {
+    val o = js("({})") as EventModifierInit
+
+    o.`ctrlKey` = ctrlKey
+    o.`shiftKey` = shiftKey
+    o.`altKey` = altKey
+    o.`metaKey` = metaKey
+    o.`modifierAltGraph` = modifierAltGraph
+    o.`modifierCapsLock` = modifierCapsLock
+    o.`modifierFn` = modifierFn
+    o.`modifierFnLock` = modifierFnLock
+    o.`modifierHyper` = modifierHyper
+    o.`modifierNumLock` = modifierNumLock
+    o.`modifierOS` = modifierOS
+    o.`modifierScrollLock` = modifierScrollLock
+    o.`modifierSuper` = modifierSuper
+    o.`modifierSymbol` = modifierSymbol
+    o.`modifierSymbolLock` = modifierSymbolLock
+    o.`view` = view
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public open class WheelEvent(typeArg: String, wheelEventInitDict: WheelEventInit = noImpl) : MouseEvent(typeArg, noImpl) {
@@ -182,11 +264,48 @@ native public open class WheelEvent(typeArg: String, wheelEventInitDict: WheelEv
     }
 }
 
-native public open class WheelEventInit : MouseEventInit() {
-    var deltaX: Double = 0.0
-    var deltaY: Double = 0.0
-    var deltaZ: Double = 0.0
-    var deltaMode: Int = 0
+native public interface WheelEventInit : MouseEventInit {
+    var deltaX: Double
+    var deltaY: Double
+    var deltaZ: Double
+    var deltaMode: Int
+}
+
+inline fun WheelEventInit(deltaX: Double = 0.0, deltaY: Double = 0.0, deltaZ: Double = 0.0, deltaMode: Int = 0, screenX: Int = 0, screenY: Int = 0, clientX: Int = 0, clientY: Int = 0, button: Short = 0, buttons: Short = 0, relatedTarget: EventTarget? = null, ctrlKey: Boolean = false, shiftKey: Boolean = false, altKey: Boolean = false, metaKey: Boolean = false, modifierAltGraph: Boolean = false, modifierCapsLock: Boolean = false, modifierFn: Boolean = false, modifierFnLock: Boolean = false, modifierHyper: Boolean = false, modifierNumLock: Boolean = false, modifierOS: Boolean = false, modifierScrollLock: Boolean = false, modifierSuper: Boolean = false, modifierSymbol: Boolean = false, modifierSymbolLock: Boolean = false, view: Window? = null, detail: Int = 0, bubbles: Boolean = false, cancelable: Boolean = false): WheelEventInit {
+    val o = js("({})") as WheelEventInit
+
+    o.`deltaX` = deltaX
+    o.`deltaY` = deltaY
+    o.`deltaZ` = deltaZ
+    o.`deltaMode` = deltaMode
+    o.`screenX` = screenX
+    o.`screenY` = screenY
+    o.`clientX` = clientX
+    o.`clientY` = clientY
+    o.`button` = button
+    o.`buttons` = buttons
+    o.`relatedTarget` = relatedTarget
+    o.`ctrlKey` = ctrlKey
+    o.`shiftKey` = shiftKey
+    o.`altKey` = altKey
+    o.`metaKey` = metaKey
+    o.`modifierAltGraph` = modifierAltGraph
+    o.`modifierCapsLock` = modifierCapsLock
+    o.`modifierFn` = modifierFn
+    o.`modifierFnLock` = modifierFnLock
+    o.`modifierHyper` = modifierHyper
+    o.`modifierNumLock` = modifierNumLock
+    o.`modifierOS` = modifierOS
+    o.`modifierScrollLock` = modifierScrollLock
+    o.`modifierSuper` = modifierSuper
+    o.`modifierSymbol` = modifierSymbol
+    o.`modifierSymbolLock` = modifierSymbolLock
+    o.`view` = view
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public open class KeyboardEvent(typeArg: String, keyboardEventInitDict: KeyboardEventInit = noImpl) : UIEvent(noImpl, noImpl) {
@@ -225,12 +344,43 @@ native public open class KeyboardEvent(typeArg: String, keyboardEventInitDict: K
     }
 }
 
-native public open class KeyboardEventInit : EventModifierInit() {
-    var key: String = ""
-    var code: String = ""
-    var location: Int = 0
-    var repeat: Boolean = false
-    var isComposing: Boolean = false
+native public interface KeyboardEventInit : EventModifierInit {
+    var key: String
+    var code: String
+    var location: Int
+    var repeat: Boolean
+    var isComposing: Boolean
+}
+
+inline fun KeyboardEventInit(key: String = "", code: String = "", location: Int = 0, repeat: Boolean = false, isComposing: Boolean = false, ctrlKey: Boolean = false, shiftKey: Boolean = false, altKey: Boolean = false, metaKey: Boolean = false, modifierAltGraph: Boolean = false, modifierCapsLock: Boolean = false, modifierFn: Boolean = false, modifierFnLock: Boolean = false, modifierHyper: Boolean = false, modifierNumLock: Boolean = false, modifierOS: Boolean = false, modifierScrollLock: Boolean = false, modifierSuper: Boolean = false, modifierSymbol: Boolean = false, modifierSymbolLock: Boolean = false, view: Window? = null, detail: Int = 0, bubbles: Boolean = false, cancelable: Boolean = false): KeyboardEventInit {
+    val o = js("({})") as KeyboardEventInit
+
+    o.`key` = key
+    o.`code` = code
+    o.`location` = location
+    o.`repeat` = repeat
+    o.`isComposing` = isComposing
+    o.`ctrlKey` = ctrlKey
+    o.`shiftKey` = shiftKey
+    o.`altKey` = altKey
+    o.`metaKey` = metaKey
+    o.`modifierAltGraph` = modifierAltGraph
+    o.`modifierCapsLock` = modifierCapsLock
+    o.`modifierFn` = modifierFn
+    o.`modifierFnLock` = modifierFnLock
+    o.`modifierHyper` = modifierHyper
+    o.`modifierNumLock` = modifierNumLock
+    o.`modifierOS` = modifierOS
+    o.`modifierScrollLock` = modifierScrollLock
+    o.`modifierSuper` = modifierSuper
+    o.`modifierSymbol` = modifierSymbol
+    o.`modifierSymbolLock` = modifierSymbolLock
+    o.`view` = view
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public open class CompositionEvent(typeArg: String, compositionEventInitDict: CompositionEventInit = noImpl) : UIEvent(noImpl, noImpl) {
@@ -239,8 +389,20 @@ native public open class CompositionEvent(typeArg: String, compositionEventInitD
     fun initCompositionEvent(typeArg: String, bubblesArg: Boolean, cancelableArg: Boolean, viewArg: Window?, dataArg: String, locale: String): Unit = noImpl
 }
 
-native public open class CompositionEventInit : UIEventInit() {
-    var data: String = ""
+native public interface CompositionEventInit : UIEventInit {
+    var data: String
+}
+
+inline fun CompositionEventInit(data: String = "", view: Window? = null, detail: Int = 0, bubbles: Boolean = false, cancelable: Boolean = false): CompositionEventInit {
+    val o = js("({})") as CompositionEventInit
+
+    o.`data` = data
+    o.`view` = view
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public open class MutationEvent : Event(noImpl, noImpl) {
diff --git a/js/js.libraries/src/generated/org.w3c.dom.kt b/js/js.libraries/src/generated/org.w3c.dom.kt
index e6d87338e55..de52b0fb431 100644
--- a/js/js.libraries/src/generated/org.w3c.dom.kt
+++ b/js/js.libraries/src/generated/org.w3c.dom.kt
@@ -1617,10 +1617,20 @@ native public open class TrackEvent(type: String, eventInitDict: TrackEventInit
         get() = noImpl
 }
 
-native public open class TrackEventInit : EventInit() {
+native public interface TrackEventInit : EventInit {
     var track: UnionAudioTrackOrTextTrackOrVideoTrack?
 }
 
+inline fun TrackEventInit(track: UnionAudioTrackOrTextTrackOrVideoTrack?, bubbles: Boolean = false, cancelable: Boolean = false): TrackEventInit {
+    val o = js("({})") as TrackEventInit
+
+    o.`track` = track
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public interface HTMLMapElement : HTMLElement {
     var name: String
         get() = noImpl
@@ -2453,10 +2463,20 @@ native public open class AutocompleteErrorEvent(type: String, eventInitDict: Aut
         get() = noImpl
 }
 
-native public open class AutocompleteErrorEventInit : EventInit() {
+native public interface AutocompleteErrorEventInit : EventInit {
     var reason: String
 }
 
+inline fun AutocompleteErrorEventInit(reason: String, bubbles: Boolean = false, cancelable: Boolean = false): AutocompleteErrorEventInit {
+    val o = js("({})") as AutocompleteErrorEventInit
+
+    o.`reason` = reason
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public interface ValidityState {
     val valueMissing: Boolean
         get() = noImpl
@@ -2531,10 +2551,20 @@ native public open class RelatedEvent(type: String, eventInitDict: RelatedEventI
         get() = noImpl
 }
 
-native public open class RelatedEventInit : EventInit() {
+native public interface RelatedEventInit : EventInit {
     var relatedTarget: EventTarget?
 }
 
+inline fun RelatedEventInit(relatedTarget: EventTarget?, bubbles: Boolean = false, cancelable: Boolean = false): RelatedEventInit {
+    val o = js("({})") as RelatedEventInit
+
+    o.`relatedTarget` = relatedTarget
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public interface HTMLDialogElement : HTMLElement {
     var open: Boolean
         get() = noImpl
@@ -2601,8 +2631,16 @@ native public interface CanvasProxy : Transferable {
     fun setContext(context: RenderingContext): Unit = noImpl
 }
 
-native public open class CanvasRenderingContext2DSettings {
-    var alpha: Boolean = true
+native public interface CanvasRenderingContext2DSettings {
+    var alpha: Boolean
+}
+
+inline fun CanvasRenderingContext2DSettings(alpha: Boolean = true): CanvasRenderingContext2DSettings {
+    val o = js("({})") as CanvasRenderingContext2DSettings
+
+    o.`alpha` = alpha
+
+    return o
 }
 
 native public open class CanvasRenderingContext2D() : RenderingContext, CanvasImageSource, ImageBitmapSource {
@@ -2766,15 +2804,30 @@ native public interface TextMetrics {
         get() = noImpl
 }
 
-native public open class HitRegionOptions {
-    var path: Path2D? = null
-    var fillRule: String = "nonzero"
-    var id: String = ""
-    var parentID: String? = null
-    var cursor: String = "inherit"
-    var control: Element? = null
-    var label: String? = null
-    var role: String? = null
+native public interface HitRegionOptions {
+    var path: Path2D?
+    var fillRule: String
+    var id: String
+    var parentID: String?
+    var cursor: String
+    var control: Element?
+    var label: String?
+    var role: String?
+}
+
+inline fun HitRegionOptions(path: Path2D? = null, fillRule: String = "nonzero", id: String = "", parentID: String? = null, cursor: String = "inherit", control: Element? = null, label: String? = null, role: String? = null): HitRegionOptions {
+    val o = js("({})") as HitRegionOptions
+
+    o.`path` = path
+    o.`fillRule` = fillRule
+    o.`id` = id
+    o.`parentID` = parentID
+    o.`cursor` = cursor
+    o.`control` = control
+    o.`label` = label
+    o.`role` = role
+
+    return o
 }
 
 native public open class ImageData : ImageBitmapSource {
@@ -2890,10 +2943,44 @@ native public open class DragEvent(type: String, eventInitDict: DragEventInit =
         get() = noImpl
 }
 
-native public open class DragEventInit : MouseEventInit() {
+native public interface DragEventInit : MouseEventInit {
     var dataTransfer: DataTransfer?
 }
 
+inline fun DragEventInit(dataTransfer: DataTransfer?, screenX: Int = 0, screenY: Int = 0, clientX: Int = 0, clientY: Int = 0, button: Short = 0, buttons: Short = 0, relatedTarget: EventTarget? = null, ctrlKey: Boolean = false, shiftKey: Boolean = false, altKey: Boolean = false, metaKey: Boolean = false, modifierAltGraph: Boolean = false, modifierCapsLock: Boolean = false, modifierFn: Boolean = false, modifierFnLock: Boolean = false, modifierHyper: Boolean = false, modifierNumLock: Boolean = false, modifierOS: Boolean = false, modifierScrollLock: Boolean = false, modifierSuper: Boolean = false, modifierSymbol: Boolean = false, modifierSymbolLock: Boolean = false, view: Window? = null, detail: Int = 0, bubbles: Boolean = false, cancelable: Boolean = false): DragEventInit {
+    val o = js("({})") as DragEventInit
+
+    o.`dataTransfer` = dataTransfer
+    o.`screenX` = screenX
+    o.`screenY` = screenY
+    o.`clientX` = clientX
+    o.`clientY` = clientY
+    o.`button` = button
+    o.`buttons` = buttons
+    o.`relatedTarget` = relatedTarget
+    o.`ctrlKey` = ctrlKey
+    o.`shiftKey` = shiftKey
+    o.`altKey` = altKey
+    o.`metaKey` = metaKey
+    o.`modifierAltGraph` = modifierAltGraph
+    o.`modifierCapsLock` = modifierCapsLock
+    o.`modifierFn` = modifierFn
+    o.`modifierFnLock` = modifierFnLock
+    o.`modifierHyper` = modifierHyper
+    o.`modifierNumLock` = modifierNumLock
+    o.`modifierOS` = modifierOS
+    o.`modifierScrollLock` = modifierScrollLock
+    o.`modifierSuper` = modifierSuper
+    o.`modifierSymbol` = modifierSymbol
+    o.`modifierSymbolLock` = modifierSymbolLock
+    o.`view` = view
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public interface Window : EventTarget, UnionMessagePortOrWindow {
     val caches: CacheStorage
         get() = noImpl
@@ -3311,10 +3398,20 @@ native public open class PopStateEvent(type: String, eventInitDict: PopStateEven
         get() = noImpl
 }
 
-native public open class PopStateEventInit : EventInit() {
+native public interface PopStateEventInit : EventInit {
     var state: Any?
 }
 
+inline fun PopStateEventInit(state: Any?, bubbles: Boolean = false, cancelable: Boolean = false): PopStateEventInit {
+    val o = js("({})") as PopStateEventInit
+
+    o.`state` = state
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public open class HashChangeEvent(type: String, eventInitDict: HashChangeEventInit = noImpl) : Event(type, eventInitDict) {
     open val oldURL: String
         get() = noImpl
@@ -3322,20 +3419,41 @@ native public open class HashChangeEvent(type: String, eventInitDict: HashChange
         get() = noImpl
 }
 
-native public open class HashChangeEventInit : EventInit() {
+native public interface HashChangeEventInit : EventInit {
     var oldURL: String
     var newURL: String
 }
 
+inline fun HashChangeEventInit(oldURL: String, newURL: String, bubbles: Boolean = false, cancelable: Boolean = false): HashChangeEventInit {
+    val o = js("({})") as HashChangeEventInit
+
+    o.`oldURL` = oldURL
+    o.`newURL` = newURL
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public open class PageTransitionEvent(type: String, eventInitDict: PageTransitionEventInit = noImpl) : Event(type, eventInitDict) {
     open val persisted: Boolean
         get() = noImpl
 }
 
-native public open class PageTransitionEventInit : EventInit() {
+native public interface PageTransitionEventInit : EventInit {
     var persisted: Boolean
 }
 
+inline fun PageTransitionEventInit(persisted: Boolean, bubbles: Boolean = false, cancelable: Boolean = false): PageTransitionEventInit {
+    val o = js("({})") as PageTransitionEventInit
+
+    o.`persisted` = persisted
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public open class BeforeUnloadEvent : Event(noImpl, noImpl) {
     var returnValue: String
         get() = noImpl
@@ -3396,7 +3514,7 @@ native public open class ErrorEvent(type: String, eventInitDict: ErrorEventInit
         get() = noImpl
 }
 
-native public open class ErrorEventInit : EventInit() {
+native public interface ErrorEventInit : EventInit {
     var message: String
     var filename: String
     var lineno: Int
@@ -3404,6 +3522,20 @@ native public open class ErrorEventInit : EventInit() {
     var error: Any?
 }
 
+inline fun ErrorEventInit(message: String, filename: String, lineno: Int, colno: Int, error: Any?, bubbles: Boolean = false, cancelable: Boolean = false): ErrorEventInit {
+    val o = js("({})") as ErrorEventInit
+
+    o.`message` = message
+    o.`filename` = filename
+    o.`lineno` = lineno
+    o.`colno` = colno
+    o.`error` = error
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public interface Navigator {
     val serviceWorker: ServiceWorkerContainer
         get() = noImpl
@@ -3517,7 +3649,7 @@ native public open class MessageEvent(type: String, eventInitDict: MessageEventI
     fun initMessageEvent(typeArg: String, canBubbleArg: Boolean, cancelableArg: Boolean, dataArg: Any?, originArg: String, lastEventIdArg: String, sourceArg: UnionMessagePortOrWindow, portsArg: Array<MessagePort>?): Unit = noImpl
 }
 
-native public open class MessageEventInit : EventInit() {
+native public interface MessageEventInit : EventInit {
     var data: Any?
     var origin: String
     var lastEventId: String
@@ -3525,6 +3657,20 @@ native public open class MessageEventInit : EventInit() {
     var ports: Array<MessagePort>
 }
 
+inline fun MessageEventInit(data: Any?, origin: String, lastEventId: String, source: UnionMessagePortOrWindow?, ports: Array<MessagePort>, bubbles: Boolean = false, cancelable: Boolean = false): MessageEventInit {
+    val o = js("({})") as MessageEventInit
+
+    o.`data` = data
+    o.`origin` = origin
+    o.`lastEventId` = lastEventId
+    o.`source` = source
+    o.`ports` = ports
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public open class EventSource(url: String, eventSourceInitDict: EventSourceInit = noImpl) : EventTarget {
     open val url: String
         get() = noImpl
@@ -3550,8 +3696,16 @@ native public open class EventSource(url: String, eventSourceInitDict: EventSour
     }
 }
 
-native public open class EventSourceInit {
-    var withCredentials: Boolean = false
+native public interface EventSourceInit {
+    var withCredentials: Boolean
+}
+
+inline fun EventSourceInit(withCredentials: Boolean = false): EventSourceInit {
+    val o = js("({})") as EventSourceInit
+
+    o.`withCredentials` = withCredentials
+
+    return o
 }
 
 native public open class WebSocket(url: String, protocols: dynamic = noImpl) : EventTarget {
@@ -3603,12 +3757,24 @@ native public open class CloseEvent(type: String, eventInitDict: CloseEventInit
         get() = noImpl
 }
 
-native public open class CloseEventInit : EventInit() {
+native public interface CloseEventInit : EventInit {
     var wasClean: Boolean
     var code: Short
     var reason: String
 }
 
+inline fun CloseEventInit(wasClean: Boolean, code: Short, reason: String, bubbles: Boolean = false, cancelable: Boolean = false): CloseEventInit {
+    val o = js("({})") as CloseEventInit
+
+    o.`wasClean` = wasClean
+    o.`code` = code
+    o.`reason` = reason
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public open class MessageChannel {
     open val port1: MessagePort
         get() = noImpl
@@ -3787,7 +3953,7 @@ native public open class StorageEvent(type: String, eventInitDict: StorageEventI
         get() = noImpl
 }
 
-native public open class StorageEventInit : EventInit() {
+native public interface StorageEventInit : EventInit {
     var key: String?
     var oldValue: String?
     var newValue: String?
@@ -3795,6 +3961,20 @@ native public open class StorageEventInit : EventInit() {
     var storageArea: Storage?
 }
 
+inline fun StorageEventInit(key: String?, oldValue: String?, newValue: String?, url: String, storageArea: Storage?, bubbles: Boolean = false, cancelable: Boolean = false): StorageEventInit {
+    val o = js("({})") as StorageEventInit
+
+    o.`key` = key
+    o.`oldValue` = oldValue
+    o.`newValue` = newValue
+    o.`url` = url
+    o.`storageArea` = storageArea
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public interface HTMLAppletElement : HTMLElement {
     var align: String
         get() = noImpl
@@ -4041,9 +4221,18 @@ native public interface HTMLImageElement : HTMLElement, CanvasImageSource, Image
 native public interface HTMLPictureElement : HTMLElement {
 }
 
-native public open class EventInit {
-    var bubbles: Boolean = false
-    var cancelable: Boolean = false
+native public interface EventInit {
+    var bubbles: Boolean
+    var cancelable: Boolean
+}
+
+inline fun EventInit(bubbles: Boolean = false, cancelable: Boolean = false): EventInit {
+    val o = js("({})") as EventInit
+
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public open class CustomEvent(type: String, eventInitDict: CustomEventInit = noImpl) : Event(type, eventInitDict) {
@@ -4052,8 +4241,18 @@ native public open class CustomEvent(type: String, eventInitDict: CustomEventIni
     fun initCustomEvent(type: String, bubbles: Boolean, cancelable: Boolean, detail: Any?): Unit = noImpl
 }
 
-native public open class CustomEventInit : EventInit() {
-    var detail: Any? = null
+native public interface CustomEventInit : EventInit {
+    var detail: Any?
+}
+
+inline fun CustomEventInit(detail: Any? = null, bubbles: Boolean = false, cancelable: Boolean = false): CustomEventInit {
+    val o = js("({})") as CustomEventInit
+
+    o.`detail` = detail
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public interface NodeList {
@@ -4078,16 +4277,30 @@ native public open class MutationObserver(callback: (Array<MutationRecord>, Muta
     fun takeRecords(): Array<MutationRecord> = noImpl
 }
 
-native public open class MutationObserverInit {
-    var childList: Boolean = false
+native public interface MutationObserverInit {
+    var childList: Boolean
     var attributes: Boolean
     var characterData: Boolean
-    var subtree: Boolean = false
+    var subtree: Boolean
     var attributeOldValue: Boolean
     var characterDataOldValue: Boolean
     var attributeFilter: Array<String>
 }
 
+inline fun MutationObserverInit(childList: Boolean = false, attributes: Boolean, characterData: Boolean, subtree: Boolean = false, attributeOldValue: Boolean, characterDataOldValue: Boolean, attributeFilter: Array<String>): MutationObserverInit {
+    val o = js("({})") as MutationObserverInit
+
+    o.`childList` = childList
+    o.`attributes` = attributes
+    o.`characterData` = characterData
+    o.`subtree` = subtree
+    o.`attributeOldValue` = attributeOldValue
+    o.`characterDataOldValue` = characterDataOldValue
+    o.`attributeFilter` = attributeFilter
+
+    return o
+}
+
 native public interface MutationRecord {
     val type: String
         get() = noImpl
@@ -4548,11 +4761,22 @@ native public open class EditingBeforeInputEvent(type: String, eventInitDict: Ed
         get() = noImpl
 }
 
-native public open class EditingBeforeInputEventInit : EventInit() {
+native public interface EditingBeforeInputEventInit : EventInit {
     var command: String
     var value: String
 }
 
+inline fun EditingBeforeInputEventInit(command: String, value: String, bubbles: Boolean = false, cancelable: Boolean = false): EditingBeforeInputEventInit {
+    val o = js("({})") as EditingBeforeInputEventInit
+
+    o.`command` = command
+    o.`value` = value
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public open class EditingInputEvent(type: String, eventInitDict: EditingInputEventInit = noImpl) : Event(type, eventInitDict) {
     open val command: String
         get() = noImpl
@@ -4560,11 +4784,22 @@ native public open class EditingInputEvent(type: String, eventInitDict: EditingI
         get() = noImpl
 }
 
-native public open class EditingInputEventInit : EventInit() {
+native public interface EditingInputEventInit : EventInit {
     var command: String
     var value: String
 }
 
+inline fun EditingInputEventInit(command: String, value: String, bubbles: Boolean = false, cancelable: Boolean = false): EditingInputEventInit {
+    val o = js("({})") as EditingInputEventInit
+
+    o.`command` = command
+    o.`value` = value
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public open class DOMPointReadOnly(x: Double, y: Double, z: Double, w: Double) {
     open val x: Double
         get() = noImpl
@@ -4594,11 +4829,22 @@ native public open class DOMPoint : DOMPointReadOnly {
         set(value) = noImpl
 }
 
-native public open class DOMPointInit {
-    var x: Double = 0.0
-    var y: Double = 0.0
-    var z: Double = 0.0
-    var w: Double = 1.0
+native public interface DOMPointInit {
+    var x: Double
+    var y: Double
+    var z: Double
+    var w: Double
+}
+
+inline fun DOMPointInit(x: Double = 0.0, y: Double = 0.0, z: Double = 0.0, w: Double = 1.0): DOMPointInit {
+    val o = js("({})") as DOMPointInit
+
+    o.`x` = x
+    o.`y` = y
+    o.`z` = z
+    o.`w` = w
+
+    return o
 }
 
 native public open class DOMRect(x: Double = 0.0, y: Double = 0.0, width: Double = 0.0, height: Double = 0.0) : DOMRectReadOnly(x, y, width, height) {
@@ -4635,11 +4881,22 @@ native public open class DOMRectReadOnly(x: Double, y: Double, width: Double, he
         get() = noImpl
 }
 
-native public open class DOMRectInit {
-    var x: Double = 0.0
-    var y: Double = 0.0
-    var width: Double = 0.0
-    var height: Double = 0.0
+native public interface DOMRectInit {
+    var x: Double
+    var y: Double
+    var width: Double
+    var height: Double
+}
+
+inline fun DOMRectInit(x: Double = 0.0, y: Double = 0.0, width: Double = 0.0, height: Double = 0.0): DOMRectInit {
+    val o = js("({})") as DOMRectInit
+
+    o.`x` = x
+    o.`y` = y
+    o.`width` = width
+    o.`height` = height
+
+    return o
 }
 
 native public open class DOMQuad {
@@ -4811,8 +5068,16 @@ native public open class DOMMatrix() : DOMMatrixReadOnly(noImpl) {
     fun setMatrixValue(transformList: String): DOMMatrix = noImpl
 }
 
-native public open class ScrollOptions {
-    var behavior: String = "auto"
+native public interface ScrollOptions {
+    var behavior: String
+}
+
+inline fun ScrollOptions(behavior: String = "auto"): ScrollOptions {
+    val o = js("({})") as ScrollOptions
+
+    o.`behavior` = behavior
+
+    return o
 }
 
 native public interface MediaQueryList {
@@ -4847,22 +5112,58 @@ native public interface CaretPosition {
     fun getClientRect(): DOMRect? = noImpl
 }
 
-native public open class ScrollOptionsHorizontal : ScrollOptions() {
+native public interface ScrollOptionsHorizontal : ScrollOptions {
     var x: Double
 }
 
-native public open class ScrollOptionsVertical : ScrollOptions() {
+inline fun ScrollOptionsHorizontal(x: Double, behavior: String = "auto"): ScrollOptionsHorizontal {
+    val o = js("({})") as ScrollOptionsHorizontal
+
+    o.`x` = x
+    o.`behavior` = behavior
+
+    return o
+}
+
+native public interface ScrollOptionsVertical : ScrollOptions {
     var y: Double
 }
 
-native public open class BoxQuadOptions {
-    var box: String = "border"
+inline fun ScrollOptionsVertical(y: Double, behavior: String = "auto"): ScrollOptionsVertical {
+    val o = js("({})") as ScrollOptionsVertical
+
+    o.`y` = y
+    o.`behavior` = behavior
+
+    return o
+}
+
+native public interface BoxQuadOptions {
+    var box: String
     var relativeTo: GeometryNode
 }
 
-native public open class ConvertCoordinateOptions {
-    var fromBox: String = "border"
-    var toBox: String = "border"
+inline fun BoxQuadOptions(box: String = "border", relativeTo: GeometryNode): BoxQuadOptions {
+    val o = js("({})") as BoxQuadOptions
+
+    o.`box` = box
+    o.`relativeTo` = relativeTo
+
+    return o
+}
+
+native public interface ConvertCoordinateOptions {
+    var fromBox: String
+    var toBox: String
+}
+
+inline fun ConvertCoordinateOptions(fromBox: String = "border", toBox: String = "border"): ConvertCoordinateOptions {
+    val o = js("({})") as ConvertCoordinateOptions
+
+    o.`fromBox` = fromBox
+    o.`toBox` = toBox
+
+    return o
 }
 
 native public marker interface UnionElementOrHTMLCollection {
diff --git a/js/js.libraries/src/generated/org.w3c.fetch.kt b/js/js.libraries/src/generated/org.w3c.fetch.kt
index 3260156cc77..bdd9c7a6650 100644
--- a/js/js.libraries/src/generated/org.w3c.fetch.kt
+++ b/js/js.libraries/src/generated/org.w3c.fetch.kt
@@ -58,7 +58,7 @@ native public open class Request(input: dynamic, init: RequestInit = noImpl) {
     fun text(): dynamic = noImpl
 }
 
-native public open class RequestInit {
+native public interface RequestInit {
     var method: String
     var headers: dynamic
     var body: dynamic
@@ -68,6 +68,20 @@ native public open class RequestInit {
     var redirect: String
 }
 
+inline fun RequestInit(method: String, headers: dynamic, body: dynamic, mode: String, credentials: String, cache: String, redirect: String): RequestInit {
+    val o = js("({})") as RequestInit
+
+    o.`method` = method
+    o.`headers` = headers
+    o.`body` = body
+    o.`mode` = mode
+    o.`credentials` = credentials
+    o.`cache` = cache
+    o.`redirect` = redirect
+
+    return o
+}
+
 native public open class Response(body: dynamic = noImpl, init: ResponseInit = noImpl) {
     open val type: String
         get() = noImpl
@@ -96,9 +110,19 @@ native public open class Response(body: dynamic = noImpl, init: ResponseInit = n
     }
 }
 
-native public open class ResponseInit {
-    var status: Short = 200
-    var statusText: String = "OK"
+native public interface ResponseInit {
+    var status: Short
+    var statusText: String
     var headers: dynamic
 }
 
+inline fun ResponseInit(status: Short = 200, statusText: String = "OK", headers: dynamic): ResponseInit {
+    val o = js("({})") as ResponseInit
+
+    o.`status` = status
+    o.`statusText` = statusText
+    o.`headers` = headers
+
+    return o
+}
+
diff --git a/js/js.libraries/src/generated/org.w3c.files.kt b/js/js.libraries/src/generated/org.w3c.files.kt
index a74ca876d34..5d74106b2af 100644
--- a/js/js.libraries/src/generated/org.w3c.files.kt
+++ b/js/js.libraries/src/generated/org.w3c.files.kt
@@ -32,8 +32,16 @@ native public open class Blob() : ImageBitmapSource {
     fun close(): Unit = noImpl
 }
 
-native public open class BlobPropertyBag {
-    var type: String = ""
+native public interface BlobPropertyBag {
+    var type: String
+}
+
+inline fun BlobPropertyBag(type: String = ""): BlobPropertyBag {
+    val o = js("({})") as BlobPropertyBag
+
+    o.`type` = type
+
+    return o
 }
 
 native public open class File(fileBits: Array<dynamic>, fileName: String, options: FilePropertyBag = noImpl) : Blob() {
@@ -43,11 +51,20 @@ native public open class File(fileBits: Array<dynamic>, fileName: String, option
         get() = noImpl
 }
 
-native public open class FilePropertyBag {
-    var type: String = ""
+native public interface FilePropertyBag {
+    var type: String
     var lastModified: Long
 }
 
+inline fun FilePropertyBag(type: String = "", lastModified: Long): FilePropertyBag {
+    val o = js("({})") as FilePropertyBag
+
+    o.`type` = type
+    o.`lastModified` = lastModified
+
+    return o
+}
+
 native public interface FileList {
     val length: Int
         get() = noImpl
diff --git a/js/js.libraries/src/generated/org.w3c.notifications.kt b/js/js.libraries/src/generated/org.w3c.notifications.kt
index c13ee9df069..6ec1052442e 100644
--- a/js/js.libraries/src/generated/org.w3c.notifications.kt
+++ b/js/js.libraries/src/generated/org.w3c.notifications.kt
@@ -61,23 +61,50 @@ native public open class Notification(title: String, options: NotificationOption
     }
 }
 
-native public open class NotificationOptions {
-    var dir: String = "auto"
-    var lang: String = ""
-    var body: String = ""
-    var tag: String = ""
+native public interface NotificationOptions {
+    var dir: String
+    var lang: String
+    var body: String
+    var tag: String
     var icon: String
     var sound: String
     var vibrate: dynamic
-    var renotify: Boolean = false
-    var silent: Boolean = false
-    var noscreen: Boolean = false
-    var sticky: Boolean = false
-    var data: Any? = null
+    var renotify: Boolean
+    var silent: Boolean
+    var noscreen: Boolean
+    var sticky: Boolean
+    var data: Any?
 }
 
-native public open class GetNotificationOptions {
-    var tag: String = ""
+inline fun NotificationOptions(dir: String = "auto", lang: String = "", body: String = "", tag: String = "", icon: String, sound: String, vibrate: dynamic, renotify: Boolean = false, silent: Boolean = false, noscreen: Boolean = false, sticky: Boolean = false, data: Any? = null): NotificationOptions {
+    val o = js("({})") as NotificationOptions
+
+    o.`dir` = dir
+    o.`lang` = lang
+    o.`body` = body
+    o.`tag` = tag
+    o.`icon` = icon
+    o.`sound` = sound
+    o.`vibrate` = vibrate
+    o.`renotify` = renotify
+    o.`silent` = silent
+    o.`noscreen` = noscreen
+    o.`sticky` = sticky
+    o.`data` = data
+
+    return o
+}
+
+native public interface GetNotificationOptions {
+    var tag: String
+}
+
+inline fun GetNotificationOptions(tag: String = ""): GetNotificationOptions {
+    val o = js("({})") as GetNotificationOptions
+
+    o.`tag` = tag
+
+    return o
 }
 
 native public open class NotificationEvent(type: String, eventInitDict: NotificationEventInit = noImpl) : ExtendableEvent(type, eventInitDict) {
@@ -85,7 +112,17 @@ native public open class NotificationEvent(type: String, eventInitDict: Notifica
         get() = noImpl
 }
 
-native public open class NotificationEventInit : ExtendableEventInit() {
+native public interface NotificationEventInit : ExtendableEventInit {
     var notification: Notification
 }
 
+inline fun NotificationEventInit(notification: Notification, bubbles: Boolean = false, cancelable: Boolean = false): NotificationEventInit {
+    val o = js("({})") as NotificationEventInit
+
+    o.`notification` = notification
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
diff --git a/js/js.libraries/src/generated/org.w3c.workers.kt b/js/js.libraries/src/generated/org.w3c.workers.kt
index ba12a5fe879..f017be5e824 100644
--- a/js/js.libraries/src/generated/org.w3c.workers.kt
+++ b/js/js.libraries/src/generated/org.w3c.workers.kt
@@ -102,10 +102,18 @@ native public interface ServiceWorkerContainer : EventTarget {
     fun getRegistrations(): dynamic = noImpl
 }
 
-native public open class RegistrationOptions {
+native public interface RegistrationOptions {
     var scope: String
 }
 
+inline fun RegistrationOptions(scope: String): RegistrationOptions {
+    val o = js("({})") as RegistrationOptions
+
+    o.`scope` = scope
+
+    return o
+}
+
 native public open class ServiceWorkerMessageEvent(type: String, eventInitDict: ServiceWorkerMessageEventInit = noImpl) : Event(type, eventInitDict) {
     open val data: Any?
         get() = noImpl
@@ -120,7 +128,7 @@ native public open class ServiceWorkerMessageEvent(type: String, eventInitDict:
     fun initServiceWorkerMessageEvent(typeArg: String, canBubbleArg: Boolean, cancelableArg: Boolean, dataArg: Any?, originArg: String, lastEventIdArg: String, sourceArg: UnionMessagePortOrServiceWorker, portsArg: Array<MessagePort>?): Unit = noImpl
 }
 
-native public open class ServiceWorkerMessageEventInit : EventInit() {
+native public interface ServiceWorkerMessageEventInit : EventInit {
     var data: Any?
     var origin: String
     var lastEventId: String
@@ -128,6 +136,20 @@ native public open class ServiceWorkerMessageEventInit : EventInit() {
     var ports: Array<MessagePort>
 }
 
+inline fun ServiceWorkerMessageEventInit(data: Any?, origin: String, lastEventId: String, source: UnionMessagePortOrServiceWorker?, ports: Array<MessagePort>, bubbles: Boolean = false, cancelable: Boolean = false): ServiceWorkerMessageEventInit {
+    val o = js("({})") as ServiceWorkerMessageEventInit
+
+    o.`data` = data
+    o.`origin` = origin
+    o.`lastEventId` = lastEventId
+    o.`source` = source
+    o.`ports` = ports
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public interface Client : UnionClientOrMessagePortOrServiceWorker {
     val url: String
         get() = noImpl
@@ -152,16 +174,34 @@ native public interface Clients {
     fun claim(): dynamic = noImpl
 }
 
-native public open class ClientQueryOptions {
-    var includeUncontrolled: Boolean = false
-    var type: String = "window"
+native public interface ClientQueryOptions {
+    var includeUncontrolled: Boolean
+    var type: String
+}
+
+inline fun ClientQueryOptions(includeUncontrolled: Boolean = false, type: String = "window"): ClientQueryOptions {
+    val o = js("({})") as ClientQueryOptions
+
+    o.`includeUncontrolled` = includeUncontrolled
+    o.`type` = type
+
+    return o
 }
 
 native public open class ExtendableEvent(type: String, eventInitDict: ExtendableEventInit = noImpl) : Event(type, eventInitDict) {
     fun waitUntil(f: dynamic): Unit = noImpl
 }
 
-native public open class ExtendableEventInit : EventInit() {
+native public interface ExtendableEventInit : EventInit {
+}
+
+inline fun ExtendableEventInit(bubbles: Boolean = false, cancelable: Boolean = false): ExtendableEventInit {
+    val o = js("({})") as ExtendableEventInit
+
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public open class FetchEvent(type: String, eventInitDict: FetchEventInit = noImpl) : ExtendableEvent(type, eventInitDict) {
@@ -174,10 +214,22 @@ native public open class FetchEvent(type: String, eventInitDict: FetchEventInit
     fun respondWith(r: dynamic): Unit = noImpl
 }
 
-native public open class FetchEventInit : ExtendableEventInit() {
+native public interface FetchEventInit : ExtendableEventInit {
     var request: Request
     var client: Client
-    var isReload: Boolean = false
+    var isReload: Boolean
+}
+
+inline fun FetchEventInit(request: Request, client: Client, isReload: Boolean = false, bubbles: Boolean = false, cancelable: Boolean = false): FetchEventInit {
+    val o = js("({})") as FetchEventInit
+
+    o.`request` = request
+    o.`client` = client
+    o.`isReload` = isReload
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
 native public open class ExtendableMessageEvent(type: String, eventInitDict: ExtendableMessageEventInit = noImpl) : ExtendableEvent(type, eventInitDict) {
@@ -194,7 +246,7 @@ native public open class ExtendableMessageEvent(type: String, eventInitDict: Ext
     fun initExtendableMessageEvent(typeArg: String, canBubbleArg: Boolean, cancelableArg: Boolean, dataArg: Any?, originArg: String, lastEventIdArg: String, sourceArg: UnionClientOrMessagePortOrServiceWorker, portsArg: Array<MessagePort>?): Unit = noImpl
 }
 
-native public open class ExtendableMessageEventInit : ExtendableEventInit() {
+native public interface ExtendableMessageEventInit : ExtendableEventInit {
     var data: Any?
     var origin: String
     var lastEventId: String
@@ -202,6 +254,20 @@ native public open class ExtendableMessageEventInit : ExtendableEventInit() {
     var ports: Array<MessagePort>
 }
 
+inline fun ExtendableMessageEventInit(data: Any?, origin: String, lastEventId: String, source: UnionClientOrMessagePortOrServiceWorker?, ports: Array<MessagePort>, bubbles: Boolean = false, cancelable: Boolean = false): ExtendableMessageEventInit {
+    val o = js("({})") as ExtendableMessageEventInit
+
+    o.`data` = data
+    o.`origin` = origin
+    o.`lastEventId` = lastEventId
+    o.`source` = source
+    o.`ports` = ports
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
+}
+
 native public interface Cache {
     fun match(request: dynamic, options: CacheQueryOptions = noImpl): dynamic = noImpl
     fun matchAll(request: dynamic = noImpl, options: CacheQueryOptions = noImpl): dynamic = noImpl
@@ -212,20 +278,42 @@ native public interface Cache {
     fun keys(request: dynamic = noImpl, options: CacheQueryOptions = noImpl): dynamic = noImpl
 }
 
-native public open class CacheQueryOptions {
-    var ignoreSearch: Boolean = false
-    var ignoreMethod: Boolean = false
-    var ignoreVary: Boolean = false
+native public interface CacheQueryOptions {
+    var ignoreSearch: Boolean
+    var ignoreMethod: Boolean
+    var ignoreVary: Boolean
     var cacheName: String
 }
 
-native public open class CacheBatchOperation {
+inline fun CacheQueryOptions(ignoreSearch: Boolean = false, ignoreMethod: Boolean = false, ignoreVary: Boolean = false, cacheName: String): CacheQueryOptions {
+    val o = js("({})") as CacheQueryOptions
+
+    o.`ignoreSearch` = ignoreSearch
+    o.`ignoreMethod` = ignoreMethod
+    o.`ignoreVary` = ignoreVary
+    o.`cacheName` = cacheName
+
+    return o
+}
+
+native public interface CacheBatchOperation {
     var type: String
     var request: Request
     var response: Response
     var options: CacheQueryOptions
 }
 
+inline fun CacheBatchOperation(type: String, request: Request, response: Response, options: CacheQueryOptions): CacheBatchOperation {
+    val o = js("({})") as CacheBatchOperation
+
+    o.`type` = type
+    o.`request` = request
+    o.`response` = response
+    o.`options` = options
+
+    return o
+}
+
 native public interface CacheStorage {
     fun match(request: dynamic, options: CacheQueryOptions = noImpl): dynamic = noImpl
     fun has(cacheName: String): dynamic = noImpl
diff --git a/js/js.libraries/src/generated/org.w3c.xhr.kt b/js/js.libraries/src/generated/org.w3c.xhr.kt
index 1058d23603a..9c055ada5a3 100644
--- a/js/js.libraries/src/generated/org.w3c.xhr.kt
+++ b/js/js.libraries/src/generated/org.w3c.xhr.kt
@@ -112,9 +112,21 @@ native public open class ProgressEvent(type: String, eventInitDict: ProgressEven
         get() = noImpl
 }
 
-native public open class ProgressEventInit : EventInit() {
-    var lengthComputable: Boolean = false
-    var loaded: Long = 0
-    var total: Long = 0
+native public interface ProgressEventInit : EventInit {
+    var lengthComputable: Boolean
+    var loaded: Long
+    var total: Long
+}
+
+inline fun ProgressEventInit(lengthComputable: Boolean = false, loaded: Long = 0, total: Long = 0, bubbles: Boolean = false, cancelable: Boolean = false): ProgressEventInit {
+    val o = js("({})") as ProgressEventInit
+
+    o.`lengthComputable` = lengthComputable
+    o.`loaded` = loaded
+    o.`total` = total
+    o.`bubbles` = bubbles
+    o.`cancelable` = cancelable
+
+    return o
 }
 
diff --git a/libraries/tools/idl2k/src/main/kotlin/gen.kt b/libraries/tools/idl2k/src/main/kotlin/gen.kt
index dfd61b5ce79..7343a127f8f 100644
--- a/libraries/tools/idl2k/src/main/kotlin/gen.kt
+++ b/libraries/tools/idl2k/src/main/kotlin/gen.kt
@@ -1,5 +1,6 @@
 package org.jetbrains.idl2k
 
+import com.sun.org.apache.bcel.internal.generic.IF_ACMPEQ
 import java.util.*
 
 private fun Operation.getterOrSetter() = this.attributes.map { it.call }.toSet().let { attributes ->
@@ -22,7 +23,7 @@ fun generateFunction(repository: Repository, function: Operation, functionName:
                                 initializer = it.defaultValue,
                                 getterSetterNoImpl = false,
                                 override = false,
-                                readOnly = true,
+                                kind = AttributeKind.ARGUMENT,
                                 vararg = it.vararg,
                                 static = it.static
                         )
@@ -66,7 +67,7 @@ fun generateAttribute(putNoImpl: Boolean, repository: Repository, attribute: Att
                 type = mapType(repository, attribute.type),
                 initializer = attribute.defaultValue,
                 getterSetterNoImpl = putNoImpl,
-                readOnly = attribute.readOnly,
+                kind = if (attribute.readOnly) AttributeKind.VAL else AttributeKind.VAR,
                 override = false,
                 vararg = attribute.vararg,
                 static = attribute.static
@@ -74,7 +75,7 @@ fun generateAttribute(putNoImpl: Boolean, repository: Repository, attribute: Att
 
 private fun InterfaceDefinition.superTypes(repository: Repository) = superTypes.map { repository.interfaces[it] }.filterNotNull()
 private fun resolveDefinitionKind(repository: Repository, iface: InterfaceDefinition, constructors: List<ExtendedAttribute> = iface.findConstructors()): GenerateDefinitionKind =
-        if (iface.dictionary || constructors.isNotEmpty() || iface.superTypes(repository).any { resolveDefinitionKind(repository, it) == GenerateDefinitionKind.CLASS }) {
+        if (constructors.isNotEmpty() || iface.superTypes(repository).any { resolveDefinitionKind(repository, it) == GenerateDefinitionKind.CLASS }) {
             GenerateDefinitionKind.CLASS
         } else {
             GenerateDefinitionKind.TRAIT
@@ -82,7 +83,7 @@ private fun resolveDefinitionKind(repository: Repository, iface: InterfaceDefini
 
 private fun InterfaceDefinition.mapAttributes(repository: Repository) = attributes.map { generateAttribute(!dictionary, repository, it) }
 private fun InterfaceDefinition.mapOperations(repository: Repository) = operations.flatMap { generateFunctions(repository, it) }
-private fun Constant.mapConstant(repository : Repository) = GenerateAttribute(name, mapType(repository, type), value, false, true, false, false, true)
+private fun Constant.mapConstant(repository : Repository) = GenerateAttribute(name, mapType(repository, type), value, false, AttributeKind.VAL, false, false, true)
 private val EMPTY_CONSTRUCTOR = ExtendedAttribute(null, "Constructor", emptyList())
 
 fun generateTrait(repository: Repository, iface: InterfaceDefinition): GenerateTraitOrClass {
@@ -132,7 +133,8 @@ fun generateTrait(repository: Repository, iface: InterfaceDefinition): GenerateT
             memberFunctions = (iface.mapOperations(repository) + extensions.flatMap { it.mapOperations(repository) }).distinct().toList(),
             constants = (iface.constants.map { it.mapConstant(repository) } + extensions.flatMap { it.constants.map { it.mapConstant(repository) } }.distinct().toList()),
             primaryConstructor = primaryConstructorWithCall,
-            secondaryConstructors = secondaryConstructorsWithCall
+            secondaryConstructors = secondaryConstructorsWithCall,
+            generateBuilderFunction = iface.dictionary
     )
 }
 
@@ -161,7 +163,8 @@ fun mapUnionType(it: UnionType) = GenerateTraitOrClass(
         memberFunctions = emptyList(),
         constants = emptyList(),
         primaryConstructor = null,
-        secondaryConstructors = emptyList()
+        secondaryConstructors = emptyList(),
+        generateBuilderFunction = false
 )
 
 fun generateUnionTypeTraits(allUnionTypes: Sequence<UnionType>): Sequence<GenerateTraitOrClass> = allUnionTypes.map(::mapUnionType)
diff --git a/libraries/tools/idl2k/src/main/kotlin/model.kt b/libraries/tools/idl2k/src/main/kotlin/model.kt
index 5acb8410eaf..1f2e1a04609 100644
--- a/libraries/tools/idl2k/src/main/kotlin/model.kt
+++ b/libraries/tools/idl2k/src/main/kotlin/model.kt
@@ -25,12 +25,19 @@ data class Repository(
         val enums: Map<String, EnumDefinition>
 )
 
-data class GenerateAttribute(val name: String, val type: Type, val initializer: String?, val getterSetterNoImpl: Boolean, val readOnly: Boolean, val override: Boolean, var vararg: Boolean, val static: Boolean)
+enum class AttributeKind {
+    VAL, VAR, ARGUMENT
+}
+data class GenerateAttribute(val name: String, val type: Type, val initializer: String?, val getterSetterNoImpl: Boolean, val kind: AttributeKind, val override: Boolean, var vararg: Boolean, val static: Boolean)
 
 val GenerateAttribute.getterNoImpl: Boolean
     get() = getterSetterNoImpl
 val GenerateAttribute.setterNoImpl: Boolean
-    get() = getterSetterNoImpl && !readOnly
+    get() = getterSetterNoImpl && kind == AttributeKind.VAR
+val GenerateAttribute.isVal: Boolean
+    get() = kind == AttributeKind.VAL
+val GenerateAttribute.isVar: Boolean
+    get() = kind == AttributeKind.VAR
 
 val Type.typeSignature: String
     get() = when {
@@ -74,7 +81,8 @@ data class GenerateTraitOrClass(
         val memberFunctions: List<GenerateFunction>,
         val constants: List<GenerateAttribute>,
         val primaryConstructor: ConstructorWithSuperTypeCall?,
-        val secondaryConstructors: List<ConstructorWithSuperTypeCall>
+        val secondaryConstructors: List<ConstructorWithSuperTypeCall>,
+        val generateBuilderFunction: Boolean
 )
 
 val GenerateFunction.signature: String
diff --git a/libraries/tools/idl2k/src/main/kotlin/render.kt b/libraries/tools/idl2k/src/main/kotlin/render.kt
index 3a4e352a8c2..16fa5680675 100644
--- a/libraries/tools/idl2k/src/main/kotlin/render.kt
+++ b/libraries/tools/idl2k/src/main/kotlin/render.kt
@@ -2,7 +2,7 @@ package org.jetbrains.idl2k
 
 import java.math.BigInteger
 
-private fun <O : Appendable> O.indent(commented: Boolean, level: Int) {
+private fun <O : Appendable> O.indent(commented: Boolean = false, level: Int) {
     if (commented) {
         append("//")
     }
@@ -11,23 +11,31 @@ private fun <O : Appendable> O.indent(commented: Boolean, level: Int) {
     }
 }
 
-private fun Appendable.renderAttributeDeclaration(arg: GenerateAttribute, override: Boolean, open: Boolean, commented: Boolean, level: Int = 1) {
-    indent(commented, level)
-
+private fun Appendable.renderAttributeDeclaration(arg: GenerateAttribute, override: Boolean, open: Boolean, omitDefaults: Boolean = false) {
     when {
         override -> append("override ")
         open -> append("open ")
+        arg.vararg -> append("vararg ")
     }
 
-    append(if (arg.readOnly) "val" else "var")
-    append(" ")
-    append(arg.name)
+    append(when(arg.kind) {
+        AttributeKind.VAL -> "val "
+        AttributeKind.VAR -> "var "
+        AttributeKind.ARGUMENT -> ""
+    })
+    append(arg.name.replaceKeywords())
     append(": ")
     append(arg.type.render())
-    if (arg.initializer != null) {
+    if (arg.initializer != null && !omitDefaults) {
         append(" = ")
         append(arg.initializer.replaceWrongConstants(arg.type))
     }
+}
+
+private fun Appendable.renderAttributeDeclarationAsProperty(arg: GenerateAttribute, override: Boolean, open: Boolean, commented: Boolean, level: Int, omitDefaults: Boolean) {
+    indent(commented, level)
+
+    renderAttributeDeclaration(arg, override, open, omitDefaults)
 
     appendln()
     if (arg.getterNoImpl) {
@@ -50,19 +58,10 @@ private fun String.replaceWrongConstants(type: Type) = when {
 }
 private fun String.replaceKeywords() = if (this in keywords) this + "_" else this
 
-private fun Appendable.renderArgumentsDeclaration(args: List<GenerateAttribute>, omitDefaults: Boolean) =
+private fun Appendable.renderArgumentsDeclaration(args: List<GenerateAttribute>, omitDefaults: Boolean = false) =
         args.map {
             StringBuilder {
-                if (it.vararg) {
-                    append("vararg ")
-                }
-                append(it.name.replaceKeywords())
-                append(": ")
-                append(it.type.render())
-                if (!omitDefaults && it.initializer != null && it.initializer != "") {
-                    append(" = ")
-                    append(it.initializer.replaceWrongConstants(it.type))
-                }
+                renderAttributeDeclaration(it, it.override, false, omitDefaults)
             }
         }.joinTo(this, ", ", "(", ")")
 
@@ -90,10 +89,6 @@ private fun Appendable.renderFunctionDeclaration(f: GenerateFunction, override:
 }
 
 private fun List<GenerateAttribute>.hasNoVars() = none { it.isVar }
-private val GenerateAttribute.isVal: Boolean
-    get() = readOnly
-private val GenerateAttribute.isVar: Boolean
-    get() = !readOnly
 
 private fun GenerateAttribute.isCommented(parent: String) = "$parent.$name" in commentOutDeclarations || "$parent.$name: ${type.render()}" in commentOutDeclarations
 private fun GenerateFunction.isCommented(parent: String) =
@@ -154,7 +149,13 @@ fun Appendable.render(allTypes: Map<String, GenerateTraitOrClass>, typeNamesToUn
             .filter { it !in superAttributes && !it.static && (it.isVar || (it.isVal && superAttributesByName[it.name]?.hasNoVars() ?: true)) }
             .map { it.dynamicIfUnknownType(allTypes.keySet()) }
             .groupBy { it.signature }.reduceValues().values().forEach { arg ->
-        renderAttributeDeclaration(arg, override = arg.signature in superSignatures, open = iface.kind == GenerateDefinitionKind.CLASS && arg.readOnly, commented = arg.isCommented(iface.name))
+        renderAttributeDeclarationAsProperty(arg,
+                override = arg.signature in superSignatures,
+                open = iface.kind == GenerateDefinitionKind.CLASS && arg.isVal,
+                commented = arg.isCommented(iface.name),
+                omitDefaults = iface.kind == GenerateDefinitionKind.TRAIT,
+                level = 1
+        )
     }
     iface.memberFunctions.filter { it !in superFunctions && !it.static }.map { it.dynamicIfUnknownType(allTypes.keySet()) }.groupBy { it.signature }.reduceValues(::betterFunction).values().forEach {
         renderFunctionDeclaration(it.fixRequiredArguments(iface.name), it.signature in superSignatures, commented = it.isCommented(iface.name))
@@ -168,10 +169,10 @@ fun Appendable.render(allTypes: Map<String, GenerateTraitOrClass>, typeNamesToUn
         indent(false, 1)
         appendln("companion object {")
         iface.constants.forEach {
-            renderAttributeDeclaration(it, override = false, open = false, level = 2, commented = it.isCommented(iface.name))
+            renderAttributeDeclarationAsProperty(it, override = false, open = false, level = 2, commented = it.isCommented(iface.name), omitDefaults = false)
         }
         staticAttributes.forEach {
-            renderAttributeDeclaration(it, override = false, open = false, level = 2, commented = it.isCommented(iface.name))
+            renderAttributeDeclarationAsProperty(it, override = false, open = false, level = 2, commented = it.isCommented(iface.name), omitDefaults = false)
         }
         staticFunctions.forEach {
             renderFunctionDeclaration(it.fixRequiredArguments(iface.name), override = false, level = 2, commented = it.isCommented(iface.name))
@@ -182,6 +183,35 @@ fun Appendable.render(allTypes: Map<String, GenerateTraitOrClass>, typeNamesToUn
 
     appendln("}")
     appendln()
+
+    if (iface.generateBuilderFunction) {
+        renderBuilderFunction(iface, allSuperTypes, allTypes.keySet())
+    }
+}
+
+fun Appendable.renderBuilderFunction(dictionary: GenerateTraitOrClass, allSuperTypes: List<GenerateTraitOrClass>, allTypes: Set<String>) {
+    val fields = (dictionary.memberAttributes + allSuperTypes.flatMap { it.memberAttributes }).distinctBy { it.signature }.map { it.copy(kind = AttributeKind.ARGUMENT) }.dynamicIfUnknownType(allTypes)
+
+    append("inline fun ${dictionary.name}")
+    renderArgumentsDeclaration(fields)
+    appendln(": ${dictionary.name} {")
+
+    indent(level = 1)
+    appendln("val o = js(\"({})\") as ${dictionary.name}")
+    appendln()
+
+    for (field in fields) {
+        indent(level = 1)
+        appendln("o.`${field.name}` = ${field.name.replaceKeywords()}")
+    }
+
+    appendln()
+
+    indent(level = 1)
+    appendln("return o")
+
+    appendln("}")
+    appendln()
 }
 
 fun betterFunction(f1: GenerateFunction, f2: GenerateFunction): GenerateFunction =