flutter_qjs

一个为flutter开发的quickjs引擎。

QuickJS

官方站点：https://bellard.org/quickjs/

中文站点：https://github.com/quickjs-zh/

QuickJS QQ群：598609506。

功能

这是一个使用quickjs为底层，为flutter开发的一个轻量级JS引擎插件。当前插件支持Windows，Linux和Android。

每个 FlutterJs 对象创建一个新的线程来执行js loop。

ES6模块中import函数已经支持可以通过dart中setModuleHandler来管理。

提供一个全局的dart函数来调用dart方法, 并且Promise 已经被支持，所以你可以使用await或者then来获取来自dart中处理的结果。dart和js直接的数据转化可以参考:

dart	js
Bool	boolean
Int	number
Double	number
String	string
Uint8List/Int32List/Int64List	ArrayBuffer
Float64List	number[]
List	Array
Map	Object
Closure(List) => Future	function(....args)

notice:

1. All the Uint8List/Int32List/Int64List sent from dart will be converted to ArrayBuffer without marked the size of elements, and the ArrayBuffer will be converted to Uint8List.

2. function can only sent from js to dart and all the arguments will be packed in a dart List object.

Getting Started

1. Create a FlutterJs object. Make sure call destroy to terminate thread and release memory when you don't need it.

FlutterJs engine = FlutterJs();
// do something ...
await engine.destroy();
engine = null;

2. Call setMethodHandler to implements dart interaction. For example, you can use Dio to implements http in js:

await engine.setMethodHandler((String method, List arg) async {
  switch (method) {
    case "http":
      Response response = await Dio().get(arg[0]);
      return response.data;
    default:
      return JsMethodHandlerNotImplement();
  }
});

and in javascript, call dart function to get data:

dart("http", "http://example.com/");

3. Call setModuleHandler to resolve js module. For example, you can use assets files as module:

await engine.setModuleHandler((String module) async {
  return await rootBundle.loadString(
      "js/" + module.replaceFirst(new RegExp(r".js$"), "") + ".js");
});

and in javascript, call import function to get module:

import("hello").then(({default: greet}) => greet("world"));

4. Use evaluate to run js script, and try-catch is needed to capture js exception.

try {
  print(await engine.evaluate(code ?? '', "<eval>"));
} catch (e) {
  print(e.toString());
}

This example contains a complete demonstration on how to use this plugin.