News from the project

On the Road to dmn-js 2.0

Published by Nico Rehwaldt on Wednesday, 28 February 2018.


Today we release the first alpha version of our rewritten DMN viewer and editor. It features a brand new decision table editor that got reworked for performance and better editing experience. Being multi-view capable at its core, the toolkit gives you better abilities to inspect and switch between the different elements inside a DMN file.

A few months ago we set out started to rebuild our DMN toolkit from the core with a focus on both usability and performance. Today we've reached an important milestone towards stability and feature parity with the old 0.x version of the toolkit.

Introducing Views

Essentially, a DMN file contains many different parts that make up a decision. Each of these parts has its own representation: Decision requirement diagram, decision table and literal expression are some of the parts that can potentially be viewed and edited. One of the improvements we wanted to tackle is to allow inspection into and navigation between these contents.

The new version of our toolkit exposes the viewable contents and allows you to build rich navigation interactions around these views:

Display DMN file contents and navigate between editors.

Refer to the updated modeler example for details on how to build tabbing on top of dmn-js.

Bye Bye Simple Mode

The simple mode for decision tables was introduced to hide technical complexity and provide editing assistance for certain, often non-technical, user groups.

However, the presence of two editing modes caused frequent confusion about where to find and edit certain pieces of information. At the same time there is no clear separation between different personas using our DMN editor as we thought there would be. Technical adapt users, for instance, would sometimes use the simple mode for convenience. On the other hand, modeling beginners or none technical users would some times like to just type once they've found their way around creating simple expressions.

This release drops the simple mode in favor of a Simple Edit menu, accessible via a small handle next to the currently focussed cell:

The simple mode got replaced by the Simple Edit menu.

The new modeless approach follows four general guidelines:

  • Always allow direct editing.
  • Offer help in an unobtrusive manner.
  • Encourage learning FEEL.
  • Don't oversimplify and hide necessary meta-data.

Improved Script Visibility

Better editing of complex scripts and improving their visibility in decision tables is an ongoing topic. Already, you may edit the expression language used for individual cells via the context menu.

To improve visibility of scripts inside the table this release adds little badges which indicate the presence of a non-default expression languages, too:

The presence of a non-default expression language, indicated by a badge.

Future releases may carry out additional improvements.

New Pre-Packaged Distribution

The new version of dmn-js discontinues our Bower bundle. Pre-built versions of the DMN modeler and viewer are now distributed directly with the dmn-js npm package and available for download via unpkg.

You may reference individual assets directly from unpkg, as it is a full-fledged CDN:

<!-- required viewer styles -->
<link rel="stylesheet" href="">
<link rel="stylesheet" href="">
<link rel="stylesheet" href="">
<link rel="stylesheet" href="">

<!-- viewer distro -->
<script src=""></script>

Checkout the new pre-packaged example to learn how to embed the toolkit without prior setup or download.

Road Ahead

We encourage you to try out the latest toolkit version via or our brand new starter example. You got feedback regarding our recent DMN toolkit changes? Tell us about it in our forums.

On the road to dmn-js@2.0.0 we still got a number of things to look into, including but not limited to:

  • restoring keyboard navigation
  • handling of multiline scripts in cells
  • adding input labels
  • adding cell annotations

Please consult our next milestone for a more comprehensive list of items we still need to work on.

This release is an alpha release. Expect changes and handle it with care!

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