How to call a Dart async function from JavaScript

Question

I try to return data from a dart async function from javascript

and i have this js._DartObject.new {Symbol(_dartObj): _…e.new} as result

I want to know how to call a dart async function in javascript that return a string

Answer 1

To call a Dart async function from JavaScript, you can use the dart_invokeAsync function provided by the dart_js_facade library. Here's an example:

1. First, add the dart_js_facade package to your dependencies in your pubspec.yaml file:

dependencies:
  dart_js_facade: ^3.0.0

1. Import the dart_js_facade package in your Dart file:

import 'package:dart_js_facade/js_facade.dart';

1. Define your async function in Dart:

Future<String> getData() async {
  // your async code here
  return "some string";
}

1. In your JavaScript code, you can call this function using the dart_invokeAsync function:

const { dart_library, dart_invokeAsync } = require('dart_sdk');

// Replace "yourDartLibraryName" with the name of your Dart library
const yourDartLibrary = dart_library('yourDartLibraryName');

// Call your async function and await the result
const result = await dart_invokeAsync(yourDartLibrary, 'getData', []);

// The result should be a string
console.log(result);

In the above example, dart_library is used to import the Dart library containing the getData function. Then, dart_invokeAsync is called with the library object, the function name, and an empty array for the arguments. Finally, the result is logged to the console.

Note that dart_invokeAsync returns a promise, so you need to use await or .then() to handle the result.

I hope this helps!