This annotation marks the experimental JS-collections API that allows to manipulate with native JS-collections The API can be removed completely in any further release.

Since Kotlin 2.0

ExperimentalJsExport

annotation class ExperimentalJsExport

Marks experimental JS export annotations.

Since Kotlin 1.4

ExperimentalJsFileName

annotation class ExperimentalJsFileName

Marks experimental JsFileName annotation.

Since Kotlin 1.9

ExperimentalJsReflectionCreateInstance

@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.ANNOTATION_CLASS, AnnotationTarget.PROPERTY, AnnotationTarget.FIELD, AnnotationTarget.LOCAL_VARIABLE, AnnotationTarget.VALUE_PARAMETER, AnnotationTarget.CONSTRUCTOR, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER, AnnotationTarget.TYPEALIAS])

annotation class ExperimentalJsReflectionCreateInstance

This annotation marks the experimental Kotlin/JS reflection API that allows to create an instance of provided KClass The API can be removed completely in any further release.

Since Kotlin 1.9

ExperimentalJsStatic

annotation class ExperimentalJsStatic

Marks the experimental JsStatic annotation.

Since Kotlin 2.0

JsAny

external interface JsAny

Any JavaScript value except null or undefined

Since Kotlin 1.8

JsArray

external class JsArray<T : JsAny?> : JsAny

JavaScript Array

Since Kotlin 1.8

JsBigInt

external class JsBigInt : JsAny

JavaScript primitive bigint

Since Kotlin 1.8

JsBoolean

external class JsBoolean : JsAny

JavaScript primitive boolean

Since Kotlin 1.8

JsClass

external interface JsClass<T : Any>

Represents the constructor of a class. Instances of JsClass can be passed to JavaScript APIs that expect a constructor reference.

Since Kotlin 1.1

JsException

class JsException : Throwable

Exception thrown by the JavaScript code. All exceptions thrown by JS code are signalled to Wasm code as JsException. One can catch such exception in Wasm, but no details of the original exception can be retrieved from it.

Since Kotlin 1.8

JsExport

@ExperimentalJsExport

@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.PROPERTY, AnnotationTarget.FUNCTION, AnnotationTarget.FILE])

expect annotation class JsExport

Exports top-level declaration on JS platform.

Since Kotlin 1.4

@ExperimentalJsExport

@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.PROPERTY, AnnotationTarget.FUNCTION, AnnotationTarget.FILE])

actual annotation class JsExport

Exports top-level declaration on JS platform.

Since Kotlin 1.3

@ExperimentalJsExport

@Target(allowedTargets = [AnnotationTarget.FUNCTION])

actual annotation class JsExport

Exports top-level declaration on JS platform.

Since Kotlin 1.8

JsExternalArgument

@ExperimentalStdlibApi

@Target(allowedTargets = [AnnotationTarget.VALUE_PARAMETER])

annotation class JsExternalArgument

When placed on a function parameter, requires the type of the passed argument to be external.

Since Kotlin 1.9

JsExternalInheritorsOnly

@ExperimentalStdlibApi

@Target(allowedTargets = [AnnotationTarget.CLASS])

annotation class JsExternalInheritorsOnly

When placed on an external interface or class, requires all its child interfaces, classes, and objects to be external as well.

Since Kotlin 1.9

JsFileName

@Target(allowedTargets = [AnnotationTarget.FILE])

@ExperimentalJsFileName

expect annotation class JsFileName(val name: String)

Specifies the name of the compiled file produced from the annotated source file instead of the default one.

Since Kotlin 1.9

@Target(allowedTargets = [AnnotationTarget.FILE])

actual annotation class JsFileName(val name: String)

Specifies the name of the compiled file produced from the annotated source file instead of the default one.

Since Kotlin 1.9

JsModule

@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.PROPERTY, AnnotationTarget.FUNCTION, AnnotationTarget.FILE])

annotation class JsModule(val import: String)

Denotes an external declaration that must be imported from native JavaScript library.

Since Kotlin 1.1

@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.PROPERTY, AnnotationTarget.FUNCTION, AnnotationTarget.FILE])

annotation class JsModule(val import: String)

Denotes an external declaration that must be imported from JavaScript module.

Since Kotlin 1.8

JsName

@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY, AnnotationTarget.CONSTRUCTOR, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER])

expect annotation class JsName(val name: String)

Gives a declaration (a function, a property or a class) specific name in JavaScript.

Since Kotlin 1.0

actual annotation class JsName(val name: String)

Gives a declaration (a function, a property or a class) specific name in JavaScript.

Since Kotlin 1.1

actual annotation class JsName(val name: String)

Specifies JavaScript name for external and imported declarations

Since Kotlin 1.8

JsNonModule

@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.PROPERTY, AnnotationTarget.FUNCTION, AnnotationTarget.FILE])

annotation class JsNonModule

Denotes an external declaration that can be used without module system.

Since Kotlin 1.1

JsNumber

external class JsNumber : JsAny

JavaScript primitive number

Since Kotlin 1.8

JSON

external object JSON

Exposes the JavaScript JSON object to Kotlin.

Since Kotlin 1.1

Json

external interface Json

An interface for indexing access to a collection of key-value pairs, where type of key is String and type of value is Any?.

Since Kotlin 1.1

JsQualifier

@Target(allowedTargets = [AnnotationTarget.FILE])

annotation class JsQualifier(val value: String)

Adds prefix to external declarations in a source file.

Since Kotlin 1.1

@Target(allowedTargets = [AnnotationTarget.FILE])

annotation class JsQualifier(val value: String)

Adds prefix to external declarations in a source file.

Since Kotlin 1.8

JsReference

sealed external interface JsReference<out T : Any> : JsAny

JavaScript value that can serve as a reference for any Kotlin value.

Since Kotlin 1.8

JsStatic

@ExperimentalJsStatic

@Target(allowedTargets = [AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER])

expect annotation class JsStatic

Specifies that an additional static method is generated from the annotated companion object member if it's a function. If the member is a property, additional static getter/setter methods are generated.

Since Kotlin 2.0

@ExperimentalJsStatic

@Target(allowedTargets = [AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER])

actual annotation class JsStatic

Since Kotlin 2.0

JsString

external class JsString : JsAny

JavaScript primitive string

Since Kotlin 1.8

nativeGetter

@Target(allowedTargets = [AnnotationTarget.FUNCTION])

annotation class ~~nativeGetter~~

Since Kotlin 1.1

nativeInvoke

@Target(allowedTargets = [AnnotationTarget.FUNCTION])

annotation class ~~nativeInvoke~~

Since Kotlin 1.1

nativeSetter

@Target(allowedTargets = [AnnotationTarget.FUNCTION])

annotation class ~~nativeSetter~~

Since Kotlin 1.1

Promise

open external class Promise<out T>(executor: (resolve: (T) -> Unit, reject: (Throwable) -> Unit) -> Unit)

Exposes the JavaScript Promise object to Kotlin.

Since Kotlin 1.1

external class Promise<out T : JsAny?>(executor: (resolve: (T) -> Unit, reject: (JsAny) -> Unit) -> Unit) : JsAny

Exposes the JavaScript Promise object to Kotlin.

Since Kotlin 1.8

RegExp

external class RegExp(pattern: String, flags: String? = definedExternally)

Exposes the JavaScript RegExp object to Kotlin.

Since Kotlin 1.1

RegExpMatch

external interface RegExpMatch

Represents the return value of RegExp.exec.

Since Kotlin 1.1

Properties

console

external val console: Console

Exposes the console API to Kotlin.

Since Kotlin 1.1

definedExternally

external val definedExternally: Nothing

The property that can be used as a placeholder for statements and values that are defined in JavaScript.

Since Kotlin 1.1

external val definedExternally: Nothing

The property that can be used as a placeholder for statements and values that are defined in JavaScript.

Since Kotlin 1.8

val <T : Any> KClass<T>.js: JsClass<T>

Obtains a constructor reference for the given KClass.

Since Kotlin 1.1

kotlin

val <T : Any> JsClass<T>.kotlin: KClass<T>

Obtains a KClass instance for the given constructor reference.

Since Kotlin 1.1

noImpl

external val ~~noImpl~~: Nothing

Since Kotlin 1.1

undefined

external val undefined: Nothing?

Exposes the JavaScript undefined property to Kotlin.

Since Kotlin 1.1

Functions

add

fun Json.add(other: Json): Json

Adds key-value pairs from other to this. Returns the original receiver.

Since Kotlin 1.1

asArray

inline fun RegExpMatch.asArray(): Array<out String?>

Converts the result of RegExp.exec to an array where the first element contains the entire matched text and each subsequent element is the text matched by each capturing parenthesis.

Since Kotlin 1.1

asDynamic

inline fun Any?.asDynamic(): dynamic

Reinterprets this value as a value of the /docs/reference/dynamic-type.html.

Since Kotlin 1.1

fun Any.~~asDynamic~~(): JsAny

fun String.~~asDynamic~~(): JsString

Reinterprets this value as a value of the Dynamic type.

Since Kotlin 1.8

dateLocaleOptions

inline fun dateLocaleOptions(init: Date.LocaleOptions.() -> Unit): Date.LocaleOptions

Since Kotlin 1.1

eval

external fun eval(expr: String): dynamic

Exposes the JavaScript eval function to Kotlin.

Since Kotlin 1.1

get

inline operator fun RegExpMatch.get(index: Int): String?

Returns the entire text matched by RegExp.exec if the index parameter is 0, or the text matched by the capturing parenthesis at the given index.

Since Kotlin 1.1

fun <T : Any> JsReference<T>.get(): T

Retrieve original Kotlin value from JsReference

Since Kotlin 1.8

operator fun <T : JsAny?> JsArray<T>.get(index: Int): T?

Since Kotlin 1.8

iterator

operator fun dynamic.iterator(): Iterator<dynamic>

Allows to iterate this dynamic object in the following cases:

Since Kotlin 1.1

external fun js(code: String): dynamic

Puts the given piece of a JavaScript code right into the calling function. The compiler replaces call to js(...) code with the string constant provided as a parameter.

Since Kotlin 1.1

external fun js(code: String): Nothing

This function allows you to incorporate JavaScript code into Kotlin/Wasm codebase. It is used to implement top-level functions and initialize top-level properties.

Since Kotlin 1.9

json