firebase_js_interop 0.0.2

Wrappers and tools for composing Firebase Cloud Functions in the Dart language

Wrappers and tools for composing Firebase Cloud Functions in the Dart language

Features

Legend

🟥	No interop
🟧	Limited interop
🟨	Partial interop
🟩	Full interop

Admin

Service	Status	Comment
App	🟩
App Check	🟥
Auth	🟥
Credential	🟥
Database	🟥
Eventarc	🟥
Extensions	🟥
Firestore	🟩
Functions	🟥
Installations	🟥
Messaging	🟧	Only message sending
Project Management	🟥
Remote Config	🟥
Security Rules	🟥
Storage	🟥

Functions

Service	Status
Alerts	🟥
Database	🟥
Eventarc	🟥
Firestore	🟩
HTTPS	🟩
Identity	🟩
PubSub	🟥
Remote Config	🟥
Scheduler	🟥
Storage	🟥
Tasks	🟥
Test Lab	🟥
Global Options	🟥
onInit	🟥

Future

Interop with the following packages is planned, but not yet implemented:

• rules-unit-testing
• firebase-functions-test

Getting started

Install the firebase tools

Usage

Project structure

Create the following dart/flutter packages:

Package	Purpose
{app}	Flutter app
{app}_core	Base core package
{app}_core_flutter	Core package for Flutter app
{app}_core_js_interop	Core package for Cloud Functions
{app}_firebase/functions	Firebase Cloud Functions

The purpose of the three core packages is as follows:

• Flutter apps (besides the web platform) cannot import js_interop code
• Transpiled dart2js code cannot transitively depend on Flutter

This means the base {app}_core package cannot depend on anything that depends on Flutter. Those dependencies should be used in {app}_core_flutter instead.

Create the Firebase project

Run firebase init in {app}_firebase. Choose javascript as the language for Cloud Functions.

Set up FCF for Dart

Make the following modifications to files in {app}_firebase:

firebase.json

Add the following ignores

{
  "functions": [
    {
      "ignore": [
        "pubspec.*",
        "src",
        "tool",
        "analysis_options.yaml",
        ".dart_tool"
      ]
    }
  ]
}

functions/.gitignore

# Compiled JavaScript files
lib/**

# https://dart.dev/guides/libraries/private-files
# Created by `dart pub`
.dart_tool/

functions/package.json

{
  "main": "lib/index.js"
}

functions/pubspec.yaml

dependencies:
  {app}_core_js_interop:
    path: ../../{app}_core_js_interop
  firebase_js_interop: latest

functions/src/index.dart

This is where the Dart Cloud Functions code lives. See below for an example.

functions/tool/build.dart

This is what compiles index.dart into an index.js file that can run on Cloud Functions

import 'package:firebase_js_interop/build.dart';

void main() async {
  await buildCloudFunctions();
}

Writing models

Create the base models in {app}_core, then augment them with json serialization in {app}_core_flutter and {app}_core_js_interop. See the example project for more details on how to use json serialization with both firebase_js_interop and cloud_firestore_odm.

Writing Cloud Functions

Writing Cloud Functions in Dart is very similar to writing them in TypeScript:

import 'dart:js_interop';
import 'dart:js_interop_unsafe';

import 'package:firebase_js_interop/functions.dart';
import 'package:firebase_js_interop/node.dart';
import 'package:firebase_js_interop/express.dart' as express;

void main() {
  exports['helloWorld'] = FirebaseFunctions.https.onRequest(
    (Request request, express.Response response) {
      return response.send('Hello from Firebase!'.toJS);
    }.toJS,
  );
}

Make sure to return promises for async operations:

import 'dart:js_interop';
import 'dart:js_interop_unsafe';

import 'package:firebase_js_interop/functions.dart';
import 'package:firebase_js_interop/js.dart';
import 'package:firebase_js_interop/node.dart';
import 'package:firebase_js_interop/admin.dart';

void main() {
  exports['onMessageCreated'] = FirebaseFunctions.firestore.onDocumentCreated(
    '/chats/{chatId}/messages/{messageId}'.toJS,
    (FirestoreEvent<DocumentSnapshot> event) {
      return promise(() async {
        await Future.delayed(const Duration(seconds: 1));
      });
    }.toJS,
  );
}

Deploying Cloud Functions

1. dart run tool/build.dart
2. firebase deploy --only functions

The compiled JS will also work in the Firebase emulators

Contributing

There are many unimplemented features. Please feel free to contribute if any necessary components are missing.

See CONTRIBUTING.md for details