fjs library

FJS - Flutter JavaScript Engine

A comprehensive Flutter library for executing JavaScript code within Flutter applications. Built on top of the QuickJS engine, FJS provides a seamless integration between Dart and JavaScript, enabling developers to run JavaScript code, use Node.js modules, and create hybrid applications.

Features

Synchronous and Asynchronous Execution: Support for both sync and async JavaScript operations
Module System: Full ES6 module support with dynamic loading capabilities
Node.js Compatibility: Built-in support for common Node.js modules
Bidirectional Communication: Call JavaScript from Dart and Dart from JavaScript
Memory Management: Fine-grained control over memory usage and garbage collection
Type Safety: Type-safe conversion between Dart and JavaScript values
Error Handling: Comprehensive error reporting and debugging capabilities

Basic Usage

import 'package:fjs/fjs.dart';

// Create an async runtime
final runtime = await JsAsyncRuntime.withOptions(
  builtin: JsBuiltinOptions.all(),
);

// Create a context
final context = await JsAsyncContext.from(runtime);

// Create an engine
final engine = JsEngine(context: context);

// Initialize the engine
await engine.initWithoutBridge();

// Execute JavaScript code
final result = await engine.eval(
  source: JsCode.code('Math.random() * 100'),
);

print('Random number: ${result.value}');

Module Usage

// Load a module from file
await engine.declareNewModule(
  module: JsModule.path('utils', '/path/to/utils.js'),
);

// Execute a function from a module
final result = await engine.eval(
  source: JsCode.code("import { add } from 'utils'; add(2, 3);"),
);

Bridge Communication

await engine.init(
  bridge: (value) async {
    print('JavaScript called: ${value.value}');
    return JsResult.ok(JsValue.string('Hello from Dart!'));
  },
);

Features

Basic Usage

Module Usage

Bridge Communication

Classes

Extensions

fjs package

fjs library