Kenolo NPM | npm.io

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: 'danger@hotmail.com'
    }
  }
};

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: ['danger@hotmail.com', 'omg@hacked.com'] },
          { 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": "danger@hacker.com", "operator": "ew", "value": ["@hacker.com", "@hazard.com"] }
new - Not ends with (an array of values)
{ "property": "danger@hacker.com", "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] }