Rule engine

Problem

We needed a way to add features on the map and suggestions/actions in the Kanban when certain conditions occurred. For example, this allowed us to script a scenario, or to generate context specific actions.

Solution

The solution that we chose was to implement a simple rule engine (see the rules folder).

Rules

Rules can be added to any GeoJSON feature in feature.property._rules, which is an array of rules. However, a rule can also be specified using an empty feature, i.e. a feature without a geometry, using the same structure. Each rule consists of an optional conditions array, and one or more actions that are executed when the condition evaluates to true.

Conditions

Conditions

Actions

Hooking things up