How do I minify JavaScript code compiled from Dart Editor?

Starting with Dart Editor version 0.7.5_r27776, you can configure dart2js options in the "Launch Configuration" menu.

On a Mac, open Launch Config options with Cmd-Shift-M. Or, select the drop-down arrow next to the green run button and select "Manage Launches":

Then, find your "run as javascript" config for your app. It will have a gray globe icon.

Look for "compiler options" and add --minify

There are two quick and easy ways to minify your complied Javascript code through the Dart Editor. The recommended way is make a small addition to your pubspec.yaml file.

Here's an example:

  Name: my-app   description: An Angular web application   dependencies:     angular: any     browser: any   transformers:   - angular 

Include this additional option and you're done:

 Name: my-app   description: An Angular web application  dependencies:    angular: any    browser: any  transformers:  - angular  - $dart2js:     {'minify':true}

The second method is to change the launch options of your app and deselect the VM setting Run in checked mode. In order words: Run > Managed Launches > Click on App Launch File > VM settings > Un-check "Run in checked mode".

I haven't tried this last option yet, but according to the documentationit should auto-minify when run in "production mode".

Source: https://www.dartlang.org/tools/pub/dart2js-transformer.html

P.S.: It is important that you set the $dart2js field with a map or it willfail to build properly. This is currently either a bug or documentation issue.