reactor-rules

A reusable Reactor script allowing creation of Thng property updates and actions in response to Thng property updates and actions on Thngs. This can be used to automate Thng property updates and values according to simple rules.

How Rules Work

Rules have two main fields:

• when - an expression that will return true if the rule is to be run.

• create - an expression returning an output object that will be created when the rule is run. This can be either an action or a property update.

The action or property update key and value that triggered the script is provided so it can inform the rule and be used to create the output action or property update. For example - when a property reaches a threshold, create an action with the new value as a customField.

Types of Rules

There are two kinds of rule available with this script:

Action Created

When an action is created in scope of the project, the outputs include creating other actions or updating the same Thng's properties.

Example: when: action => action.type === '_LeftWarehouse',

Property Created/Updated

When a Thng's properties are created or updated, the outputs include creating actions or updating the same Thng's properties.

Example: when: (key, value) => key === 'temperature_celsius' && value >= 100

Installation

1. Open the Dashboard and create a project and application.
2. Paste main.js into the application's Reactor script field.
3. Click 'Show dependencies' and set the dependencies to those in package.json.
4. Save the new script with the 'Update' button.

Configuration

After installing the Reactor script, choose some rules according to the description above by configuring the ACTION_RULES and PROPERTY_RULES arrays in the script body.

The following is an example rule configuration that can be placed at the top of main.js:

const ACTION_RULES = [{
  when: action => action.type === '_LeftWarehouse',
  create: action => ({ key: 'in_transit', value: true }),
}, {
  when: action => action.type === '_ArrivedAtDestination',
  create: action => ({ key: 'in_transit', value: false }),
}];

const PROPERTY_RULES = [{
  when: (key, value) => key === 'temperature_celsius' && value >= 100,
  create: () => ({ key: 'overheating', value: true }),
}, {
  when: (key, value) => key === 'temperature_celsius' && value < 100,
  create: () => ({ key: 'overheating', value: false }),
}, {
  when: (key, value) => key === 'weather_report' && value.includes('rain'),
  create: (key, value) => ({
    type: '_ForecastAlert',
    customFields: { conditions: value },
  }),
}];

Usage

Create actions or update properties on Thngs that match the rules you have configured. You should observe the outputs being created as configured, or an error if the rule is not valid or some other problem occurred.