node_interop

Description:

node interop

Node Interop #
Write applications in Dart, run in NodeJS.

What is this?
Example
Structure
Status

Looking for latest updates? Make sure to check the most recent 1.0.0-dev.* release!
What is this? #
This library provides JavaScript bindings and some utilities to work with
core Node APIs and built-in modules.

To compile Dart applications as Node modules see build_node_compilers
package.
For a more Dart-like experience with Node I/O system see
node_io package which is designed as a drop-in replacement for dart:io.
For a Dart-style HTTP client checkout node_http.

Example #
Here is an example Node app written in Dart:
import 'package:node_interop/node.dart';

void main() {
print("Hello world, I'm currently in ${process.cwd()}.");
}
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This application can be compiled with build_node_compilers and executed in
Node.
For more examples using different APIs see example/ folder.
Structure #
For each built-in Node module there is a separate Dart file in the lib/
folder. So to access Node's os module, for instance, you'd need to use
following import:
import 'package:node_interop/os.dart';
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Note that after importing a module like above there is no need to also require
it (the Node way). Each library file (like os.dart) exposes library-level
property of the same name which gives you access to that module's functionality.
This is just a convenience to not have to import and require modules at
the same time. Here is how os.dart implements it:
// file:lib/os.dart
@JS()
library node_interop.os;

import 'package:js/js.dart';

import 'node.dart';

OS get os => require('os');

@JS()
@anonymous
abstract class OS {
external List<CPU> cpus();
// ...
}
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Not all built-in Node modules need to be required, like buffer module for
instance. They still have a dedicated Dart file in this library, but this is
mostly for consistency and you shouldn't need to import it directly. The
buffer module is globally available in Node.
Libraries with underscores in their name (like child_process) expose
library-level property with underscores converted to camelCase to be compliant
with Dart code style rules:
import 'package:node_interop/child_process.dart';

void main() {
childProcess.execSync('ls -la');
}
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Note on creating native Node.js objects #
Most of the objects in Node.js are not global therefore they are declared as
@anonymous in this library. Unfortunately this prevents us from instantiating
new instances by simply using new Something().
As a workaround for this problem each module provides a createX() library
function. For instance, stream module provides createReadable and
createWritable for creating custom Readable and Writable streams:

import 'dart:js_util'; // provides callConstructor()

/// The "stream" module's object as returned from [require] call.
StreamModule get stream => _stream ??= require('stream');
StreamModule _stream;

@JS()
@anonymous
abstract class StreamModule {
/// Reference to constructor function of [Writable].
dynamic get Writable;

/// Reference to constructor function of [Readable].
dynamic get Readable;
}

/// Creates custom [Writable] stream with provided [options].
///
/// This is the same as `callConstructor(stream.Writable, [options]);`.
Writable createWritable(WritableOptions options) {
return callConstructor(stream.Writable, [options]);
}
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Status #
Version 1.0.0 is considered stable though not feature complete. It is recommended to check
1.0.0-dev.* versions for latest updates and bug fixes.
Make sure to checkout CHANGELOG.md after every release, all
notable changes and upgrade instructions will be described there.
If you found a bug, please don't hesitate to create an issue in the
issue tracker.
Below is a list of built-in Node.js modules this library already provides
bindings for:

buffer
child_process
cluster
console
dns
domain
events
fs
http
https
module
net
os
path
process
querystring
readline
stream
string_decoder
timers
tls
tty
dgram
url
util
v8
vm
zlib

Features and bugs #
Please file feature requests and bugs at the issue tracker.