web 0.5.1 web: ^0.5.1 copied to clipboard
Lightweight browser API bindings built around JS static interop.
Lightweight browser API bindings built around JS static interop.
What's this? #
This package exposes browser APIs. It's generated from the Web IDL definitions and uses recent Dart language features for zero-overhead bindings.
This package is intended to replace
dart:html
and
similar Dart SDK libraries. It will support access to browser APIs from Dart
code compiled to either JavaScript or WebAssembly.
Usage #
import 'package:web/web.dart';
void main() {
final div = document.querySelector('div')!;
div.text = 'Text set at ${DateTime.now()}';
}
Migrating to package:web #
package:web
is replacing dart:html
and other web libraries as Dart's
long-term web interop solution. To learn how to migrate from dart:html
APIs to package:web
, see our
migration guide.
Generation conventions #
The generator scripts use a number of conventions to consistently handle Web IDL definitions:
Interfaces #
- Interfaces are emitted as extension types that wrap and implement
JSObject
. - Interface inheritance is maintained using
implements
between extension types. - Members of partial interfaces, partial mixins, and mixins are added to the interfaces that include them, and therefore do not have separate declarations.
Types #
- Generic types include the generic in the case of
JSArray
andJSPromise
. - Enums are typedef'd to
String
. - Callbacks and callback interfaces are typedef'd to
JSFunction
. - In general, we prefer the Dart primitive over the JS type equivalent wherever
possible. For example, APIs use
String
instead ofJSString
. - If a type appears in a generic position and it was typedef'd to a Dart
primitive type, it is replaced with the JS type equivalent to respect the type
bound of
JSAny?
. - Union types are computed by picking the least upper bound of the types in the
JS type hierarchy, where every interface is equivalent to
JSObject
.
Compatibility #
- The generator uses the MDN compatibility data to determine what members and interfaces to emit. Currently, we only emit code that is standards track and supported on Chrome, Firefox, and Safari to reduce the number of breaking changes. This is currently WIP and some members may be added or removed.
Generation and updating the package #
Most of the APIs in this package are generated from public assets. See tool/README.md for information on the spec and IDL versions the package was generated from, and for the process for updating the package.