dart:js_interop library

Interoperability with JavaScript and browser APIs.

The JSObject type hierarchy is modeled after the JavaScript type hierarchy, and facilitates sound interoperability with JavaScript.

Note

The types defined in this library only provide static guarantees. The runtime types differ based on the backend, so it is important to rely on static functionality like the conversion functions, for example toJS and not runtime mechanisms like type checks (is) and casts (as).

Classes

JS
The annotation for JS interop members.
JSExport
Annotation to allow Dart classes to be wrapped with a JS object using dart:js_interop's createJSInteropWrapper.

Extension Types

JSAny
The overall top type in the JS types hierarchy.
JSArray
The type of all JS arrays.
JSArrayBuffer
The JavaScript ArrayBuffer.
JSBigInt
The JavaScript BigInt.
JSBoolean
The Javascript booleans.
JSBoxedDartObject
A boxed Dart object that can be passed to JavaScript safely.
JSDataView
The JavaScript DataView.
JSExportedDartFunction
A JavaScript callable function created from a Dart function.
JSFloat32Array
The JavaScript Float32Array.
JSFloat64Array
The Javascript Float64Array.
JSFunction
The type of all JS functions.
JSInt16Array
The JavaScript Int16Array.
JSInt32Array
The JavaScript Int32Array.
JSInt8Array
The JavaScript Int8Array.
JSNumber
The JavaScript numbers.
JSObject
The representation type of all JavaScript objects for extension types.
JSPromise
A JavaScript Promise or a promise-like object.
JSString
The JavaScript strings.
JSSymbol
The JavaScript Symbols.
JSTypedArray
The abstract supertype of all JS typed arrays.
JSUint16Array
The Javascript Uint16Array.
JSUint32Array
The Javascript Uint32Array.
JSUint8Array
The JavaScript Uint8Array.
JSUint8ClampedArray
The Javascript Uint8ClampedArray.

Extensions

BoolToJSBoolean
Conversion from bool to JSBoolean.
ByteBufferToJSArrayBuffer
Conversion from ByteBuffer to JSArrayBuffer.
ByteDataToJSDataView
Conversion from ByteData to JSDataView.
DoubleToJSNumber
Conversion from double to JSNumber.
Float32ListToJSFloat32Array
Conversion from Float32List to JSFloat32Array.
Float64ListToJSFloat64Array
Conversion from Float64List to JSFloat64Array.
FunctionToJSExportedDartFunction
Conversion from Function to JSExportedDartFunction.
FutureOfJSAnyToJSPromise
FutureOfVoidToJSPromise
Conversion from Future to JSPromise.
Int16ListToJSInt16Array
Conversion from Int16List to JSInt16Array.
Int32ListToJSInt32Array
Conversion from Int32List to JSInt32Array.
Int8ListToJSInt8Array
Conversion from Int8List to JSInt8Array.
JSAnyOperatorExtension
JSAnyUtilityExtension
Common utility functions that are useful for any JS value.
JSArrayBufferToByteBuffer
Conversion from JSArrayBuffer to ByteBuffer.
JSArrayToList
Conversion from JSArray to List.
JSBooleanToBool
Conversion from JSBoolean to bool.
JSBoxedDartObjectToObject
Conversion from JSBoxedDartObject to Object.
JSDataViewToByteData
Conversion from JSDataView to ByteData.
JSExportedDartFunctionToFunction
Conversion from JSExportedDartFunction to Function.
JSFloat32ArrayToFloat32List
Conversion from JSFloat32Array to Float32List.
JSFloat64ArrayToFloat64List
Conversion from JSFloat64Array to Float64List.
JSFunctionUtilExtension
Utility extensions for JSFunction.
JSInt16ArrayToInt16List
Conversion from JSInt16Array to Int16List.
JSInt32ArrayToInt32List
Conversion from JSInt32Array to Int32List.
JSInt8ArrayToInt8List
Conversion from JSInt8Array to Int8List.
JSNumberToNumber
Conversion from JSNumber to double or int.
JSPromiseToFuture
Conversion from JSPromise to Future.
JSStringToString
Conversion from JSString to String.
JSUint16ArrayToInt16List
Conversion from JSUint16Array to Uint16List.
JSUint32ArrayToUint32List
Conversion from JSUint32Array to Uint32List.
JSUint8ArrayToUint8List
Conversion from JSUint8Array to Uint8List.
JSUint8ClampedArrayToUint8ClampedList
Conversion from JSUint8ClampedArray to Uint8ClampedList.
ListToJSArray
Conversion from List to JSArray.
NullableObjectUtilExtension
Utility extensions for Object?.
NullableUndefineableJSAnyExtension
JS undefined and JS null are internalized differently based on the backends. In the JS backends, Dart null can actually be JS undefined or JS null. In dart2wasm, that's not the case: there's only one Wasm value null can be. Therefore, when we get back JS null or JS undefined, we internalize both as Dart null in dart2wasm, and when we pass Dart null to an interop API, we pass JS null. In the JS backends, Dart null retains its original value when passed back to an interop API. Be wary of writing code where this distinction between null and undefined matters.
NumToJSExtension
Conversion from num to JSNumber.
ObjectToJSBoxedDartObject
StringToJSString
Conversion from String to JSString.
Uint16ListToJSInt16Array
Conversion from Uint16List to JSUint16Array.
Uint32ListToJSUint32Array
Conversion from Uint32List to JSUint32Array.
Uint8ClampedListToJSUint8ClampedArray
Conversion from Uint8ClampedList to JSUint8ClampedArray.
Uint8ListToJSUint8Array
Conversion from Uint8List to JSUint8Array.

Constants

anonymous → const _Anonymous
An annotation that indicates a JS annotated class is structural and does not have a known JavaScript prototype.
staticInterop → const _StaticInterop
staticInterop enables the JS annotated class to be treated as a "static" interop class.

Properties

globalContext → JSObject
A getter to retrieve the global context that is used in static interop lowering.
no setter

Functions

createJSInteropWrapper<T extends Object>(T dartObject) → JSObject
Given a Dart object that is marked "exportable", creates a JS object that wraps the given Dart object. Look at the @JSExport annotation to determine what constitutes "exportable" for a Dart class. The object literal will be a map of export names (which are either the written instance member names or their rename) to their respective Dart instance members.
importModule(String moduleName) → JSPromise<JSObject>
Call to dynamically import a JS module with the given moduleName using the JS import() syntax.

Typedefs

JSVoid = void
The type of JSUndefined when returned from functions. Unlike pure JS, no actual object will be returned.

Exceptions / Errors

NullRejectionException
Exception for when the promise is rejected with a null or undefined value.