dart compile

Use the dart compile command to compile a Dart program to a target platform. The output — which you specify using a subcommand — can either include a Dart runtime or be a snapshot.

Here’s an example of using the exe subcommand to produce a self-contained executable file (myapp.exe):

$ dart compile exe bin/myapp.dart
Generated: /Users/me/myapp/bin/myapp.exe

The next example uses the aot-snapshot subcommand to produce a snapshot (myapp.aot). It then uses the dartaotruntime command (which provides a Dart runtime) to run the snapshot:

$ dart compile aot-snapshot bin/myapp.dart
Generated: /Users/me/myapp/bin/myapp.aot
$ dartaotruntime bin/myapp.aot

To specify the path to the output file, use the -o or --output option:

$ dart compile exe bin/myapp.dart -o bin/runme

For more options and usage information, run dart compile [<subcommand>] --help:

$ dart compile exe --help

The dart compile command replaces the dart2native, dart2aot, and dart2js commands.

Types of output

The following table shows the subcommands of dart compile.

Self-contained executables (exe)

The exe subcommand produces a standalone executable for Windows, macOS, or Linux. A standalone executable is native machine code that’s compiled from the specified Dart file and its dependencies, plus a small Dart runtime that handles type checking and garbage collection.

You can distribute and run the output file like you would any other executable file:

$ dart compile exe bin/myapp.dart -o /tmp/myapp
Generated: /tmp/myapp
$ cd /tmp
$ ./myapp

Known limitations

The exe and aot-snapshot subcommands have some known limitations:

No cross-compilation support (issue 28617)

The compiler supports creating machine code only for the operating system it’s running on. You need to run the compiler three times — on macOS, Windows, and Linux — to create executables for all three operating systems. A workaround is to use a CI (continuous integration) provider that supports all three operating systems.

No signing support (issue 39106)

The format of the executables isn’t compatible with standard signing tools such as codesign and SignTool.

No support for dart:mirrors and dart:developer

For a complete list of the core libraries you can use, see the All and AOT entries in the table of core Dart libraries.

AOT snapshots (aot-snapshot)

Use AOT snapshots to reduce disk space requirements when distributing multiple command-line apps. The aot-snapshot subcommand produces an output file that’s specific to the current architecture. For example, if you use macOS to create a .aot file, then that file can run on macOS only. AOT snapshots are supported on Windows, macOS, and Linux.

$ dart compile aot-snapshot bin/myapp.dart
Generated: /Users/me/myapp/bin/myapp.aot
$ dartaotruntime bin/myapp.aot

For more information, see Known limitations and the dartaotruntime documentation.

JIT snapshots (jit-snapshot)

JIT snapshots include all the parsed classes and compiled code that’s generated during a training run of a program.

$ dart compile jit-snapshot bin/myapp.dart
Compiling bin/myapp.dart to jit-snapshot file bin/myapp.jit.
Hello world!
$ dart run bin/myapp.jit
Hello world!
$

When running from an application snapshot, the Dart VM doesn’t need to parse or compile classes and functions that were already used during the training run, so the VM starts running user code sooner.

These snapshots are architecture specific, unlike snapshots produced using the kernel subcommand.

Portable snapshots (kernel)

Use the kernel subcommand to package up an app into a single, portable file that can be run on all operating systems and CPU architectures. A kernel snapshot contains a binary form of the abstract syntax tree (Kernel AST) for a Dart program.

Here’s an example of creating and running a kernel snapshot:

$ dart compile kernel bin/myapp.dart
Compiling bin/myapp.dart to kernel file bin/myapp.dill.
$ dart run bin/myapp.dill

Although kernel snapshots have reduced startup time compared to Dart code, they can have much slower startup than architecture-specific AOT output formats.

JavaScript (js)

The js subcommand compiles Dart code to deployable JavaScript. Another Dart-to-JavaScript compiler, dartdevc, is for development use only.

You usually use the webdev tool instead of directly using a Dart-to-JavaScript compiler. The webdev build command, by default, produces deployable JavaScript. The webdev serve command uses dartdevc by default, but you can switch to producing deployable JavaScript by using the --release flag.

For more information, see the dart2js documentation.