README.md

bullet-train-rules-engine

This project is the JavaScript rules engine that powers user segments for bullet-train.io.

Features

It allows for a recursive ruleset, with ANY ALL and NONE predicates. It supports the following types of operators:

• 'CONTAINS'
• 'EQUAL'
• 'GREATER_THAN'
• 'GREATER_THAN_INCLUSIVE'
• 'LESS_THAN'
• 'NOT_CONTAINS'
• 'NOT_EQUAL'
• 'REGEX'

Installation

npm i bullet-train-rules-engine --save

Usage

import rulesEngine from 'bullet-train-rules-engine'

// The object to test
const test = {
    favouriteColour: 'blue',
    hasConfirmedEmail: true,
    name: 'kyle',
    deepObject: {
        hiddenProperty: true
    }
};

// The ruleset
const rules = [
    {
        property: 'favouriteColour',
        operator: 'EQUAL',
        value: 'blue'
    },
    {
        any: {
            rules: [
                {
                    property: 'money',
                    operator: 'GREATER_THAN_INCLUSIVE',
                    value: 11
                },
                {
                    property: 'hasConfirmedEmail',
                    operator: 'EQUAL',
                    value: true
                },
                {
                    property: 'deepObject.hiddenProperty',
                    operator: 'EQUAL',
                    value: true
                },
                {
                    property: 'favouriteColour',
                    operator: 'NOT_CONTAINS',
                    value: 'blue'
                },
                {
                    none: {
                        rules: [
                            {
                                property: 'favouriteColour',
                                operator: 'EQUALS',
                                value: 'green'
                            },
                            {
                                property: 'money',
                                operator: 'EQUALS',
                                value: 99
                            },
                        ]
                    }
                }
            ]
        },
    },
    {
        all: {
            rules: [
                {
                    property: 'name',
                    operator: 'REGEX',
                    value: 'ky.*?e'
                },
            ]
        }
    }
];

   rulesEngine(test, rules)
            .then(({result, rules}) => {
              // use the overall result and see a breakdown of which rules comply
            });

Rule syntax:

The rules engine expects an array of rules, rule objects are either:

All, any, none rules Evaluate to true or false based on evaluating all child rules. Child rules can be leaf rules or nested All/any/none rules,

• ALL: every child rule must evaluate as true
• ANY: at least one of the child rules must evaluate as true
• NONE: at least one of the child rules must evaluate as true

{
    all: {
        rules: [
            { // Nested all, any, none rule
                all|any|none: {
                    rules: [...]
                }
            },
            { // Leaf rule
                property:'',
                operator:'',
                value:'',
            }
        ]
    }
}

Leaf rules Evaluate to true or false based on the tested value, expected value and operator.

{
  property: 'eyeColour', // The name of the property that is being targeted .e.g
  operator: 'EQUALS', // The operator
  value: 'blue' // The expected value
}

Run the example at localhost:3000

Clone the repository and run:

npm i
npm start

Contributing

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

Getting Help

If you encounter a bug or feature request we would like to hear about it. Before you submit an issue please search existing issues in order to prevent duplicates.

Get in touch

If you have any questions about our projects you can email [email protected].