jexl.md

Javascript Expression Language

Caluma relies on Javascript Expression Language alias JEXL for defining powerful yet simple expressions for complex validation and flow definitions. Reason for using JEXL over other languages is that it can be simply implemented in the backend and frontend as of its defined small scope. This allows frontends in the browser to validate data in exactly the same way as the server will, while not limiting validation to simple regexes.

This speeds up user interaction a good deal. JEXL expressions are used in the following contexts:

• Deciding whether a field should be visible or not (is_hidden property)
• Deciding whether a field is required (is_required property)
• Deciding what groups should be addressed in a WorkItem
• Deciding what groups should have a controlling function on a WorkItem
• Deciding what Task should be used for the next WorkItem

Within the expressions, you can access various information about the context.

Specific information about the usage of jexl expression can be found in their respective documentation:

• Document validation
• Workflow WorkItem assignments