KENOLO

A lightweight JSON-based business rules engine

Consider Using KENOLO, If:

• You want non-programmers to be able to understand and modify the rules themselves
  KENOLO ruleset is simple yet powerful thanks to the operators which are supported
• You need to apply different rules and conditions per environment
  Use npm configuration packages, such as config or nconf, to store your ruleset per environment.
• Rules are frequently changed, but you strive to keep source code modifications and consequently tedious QA cycles to the minimum
  Simply modify an external JSON file to update your ruleset.
• Security, size & performance concern you
  KENOLO is a 22KB eval-free npm package.

Installation

npm i kenolo -S

Ruleset Structure

{
  "NAME_OF_RULE_1": {
    // mandatory - object of one or more conditions to check whether rule should apply:
    "include":
      // condition 1:
      { "name": "CONDITION_NAME", "property": "PROPERTY_PATH_TO_EXTRACT_DATA_FROM", "operator": "eq", "value": "VALUE_TO_COMPARE_WITH" },
    // optional - object of one or more conditions to check whether rule should NOT apply:
    "exclude": {
      // array of conditions which should all be truthy for rule to apply:
      "and": [
        // condition 1:
        { "name": "CONDITION_NAME", "property": "PROPERTY_PATH_TO_EXTRACT_DATA_FROM", "operator": "gt", "value": "VALUE_TO_COMPARE_WITH" },
        // condition 2:
        { "name": "CONDITION_NAME", "property": "PROPERTY_PATH_TO_EXTRACT_DATA_FROM", "operator": "neq", "value": "VALUE_TO_COMPARE_WITH" },
        // more conditions:
        //...
      ],
      // array of conditions from which at least one of them should be truthy for rule to apply:
      "or": [
        // condition 1:
        { "name": "CONDITION_NAME", "property": "PROPERTY_PATH_TO_EXTRACT_DATA_FROM", "operator": "eq", "value": "VALUE_TO_COMPARE_WITH" },
        // condition 2:
        { "name": "CONDITION_NAME", "property": "PROPERTY_PATH_TO_EXTRACT_DATA_FROM", "operator": "eq", "value": "VALUE_TO_COMPARE_WITH" },
        // more conditions:
        //...
      ]
    }
  },
  "NAME_OF_RULE_2": {
    "include": [
      // ...
    ]
  }
}

Basic Example

const kenolo = require('kenolo');

const data = {
  order: {
    status: 2,
    user: {
      email: '[email protected]'
    }
  }
};

const SHOULD_REVIEW = {
  include: {
    and: [
      { name: 'STATUS_PENDING', property: 'order.status', operator: 'eq', value: 2 },
      {
        or: [
          { name: 'HIGH_RISK_USER_EMAILS', property: 'order.user.email', operator: 'in', value: ['[email protected]', '[email protected]'] },
          { name: 'MAX_PRICE_EXCEEDED', property: 'order.price', operator: 'gt', value: 500 }
        ]
      }
    ]
  }
};

kenolo(SHOULD_REVIEW, data);
// -> { apply: true, conditions: [ 'STATUS_PENDING', 'HIGH_RISK_USER_EMAILS' ] }

See tests directory for more examples

Response Object

{
  // {Boolean} apply - Should rule apply?
  apply: true,
  // {String[]} conditions - Truthy condition names
  conditions: ['CONDITION_NAME_1', 'CONDITION_NAME_2']
}

Supported Operators

• ex - Property exists
  { "property": "a", "operator": "ex" }

• nex - Property doesn't exists
  { "property": "a", "operator": "nex" }

• eq - Equals to (a single value)
  { "property": "a", "operator": "eq", "value": "a" }

• neq - Not equals to (a single value)
  { "property": "a", "operator": "neq", "value": "b" }

• weq - Weak equals to (a single value)
  { "property": "2", "operator": "weq", "value": 2 }

• nweq - Not weak equals to (a single value)
  { "property": "a", "operator": "nweq", "value": "b" }

• in - In (an array of values)
  { "property": "a", "operator": "in", "value": ["a", "b", "c"] }

• nin - Not in (an array of values)
  { "property": "d", "operator": "nin", "value": ["a", "b", "c"] }

• gt - Greater than (a single value)
  { "property": 100, "operator": "gt", "value": 80 }

• gte - Greater than or equals to (a single value)
  { "property": 100, "operator": "gte", "value": 100 }

• lt - Lower than (a single value)
  { "property": 100, "operator": "lt", "value": 120 }

• lte - Lower than or equals to (a single value)
  { "property": 100, "operator": "lte", "value": 100 }

• sw - Starts with (an array of values)
  { "property": "+1 40 9871625", "operator": "sw", "value": ["+1", "+40"] }

• nsw - Not starts with (an array of values)
  { "property": "+1 40 9871625", "operator": "nsw", "value": ["+1", "+40"] }

• ew - Ends with (an array of values)
  { "property": "[email protected]", "operator": "ew", "value": ["@hacker.com", "@hazard.com"] }

• new - Not ends with (an array of values)
  { "property": "[email protected]", "operator": "new", "value": ["@hacker.com", "@hazard.com"] }

• inc - Includes (an array of values)
  { "property": "John", "operator": "inc", "value": ["oh", "bla"] }

• ninc - Not includes (an array of values)
  { "property": "John", "operator": "ninc", "value": ["oh", "bla"] }

• sl - Sounds like (an array of values)
  { "property": "John", "operator": "sl", "value": ["Jon", "David"] }

• re - Regular expression (an array of values)
  { "property": "New York", "operator": "re", "value": [/New/i] }
{ "property": "New York", "operator": "re", "value": ["\\w+"] }

Array properties

• some - Some are included (an array of values)
  { "property": [1, 2, 3], "operator": "some", "value": [1, 5, 8] }
• every - All are included (an array of values)
  { "property": [1, 2, 3], "operator": "every", "value": [1, 2, 3, 4, 5] }
• none - None are included (an array of values)
  { "property": [1, 2, 3], "operator": "none", "value": [4, 5, 7, 8] }