tevale v0.9.2

tevale

Tevale is the tiny evaluator of expressions, which accepts a set of variables (named objects with properties) and an expression, validates its syntax and evaluates the expression.

Developed in Codefresh.

Its goal is to allow the evaluations of expressions (in a variable context) so as to generate a boolean true/false result. It was designed to be embeded into scripts that contain various entities and require the evaluation of an expression to make a yes/no decision.

Features

• Validation and evaluation of expressions
• Supports variables in expressions, including object variables (nesting)
• Supports popular functions and operators for number and string manipulation
• Supports string searching and regexp matching functions

Installation

$ npm install cf-expression-evaluator --save

Usage

const tevale = require('tevale');
const variables = {
    "author": {
        "name": "Alon Diamant",
        "homepage": "http://www.alondiamant.com",
        "github": {
            "repositories": 12,
            "url": "http://www.github.com/advance512"
        },
    },
    "company": {
        "name": "Codefresh",
        "homepage": "http://www.codefresh.io",
        "phoneNumber": "+972-99-999-9999"
    }
}

console.log(
    tevale.evaluateExpression(
        'match(author.name, "alon", true) && ' +
        'author.github.repositories > 10 && ' +
        'Number(substring(company.phoneNumber, 1, 4)) / 2 == 486',
        variables
    )
);

Reference

Types

Variables and Members

• You can then use the members of each variable.
• To access variables that have a non-standard (i.e. only alphanumeric and _ characters) names, use the Variable() function.
• To access variable members that have a non-standard (i.e. only alphanumeric and _ characters) names, use the Member() function.

Unary Operators

Binary Operators

Comparisons

Functions

Examples

Using the variables:

const exampleVariables = {
    'somePositiveNumericValue': 123,
    'someZeroValue': 0,
    'someNegativeNumericValue': -50,
    'stringValue': 'hello',
    'emptyStringValue': '',
    'longStringValue': 'mA26EKMPupgvp6XYlGAVJZKv6yvaD3aobXMyExvyMBa2Hi9LlJXTUaBveMR9ErHtSfXNHHW5xAKbz2DVfBOqQ8CaSMNMQRBrJRpEpsO7FygKZmKpKHvvtPviOTfyUE0HGhnSPYHb9Hbz1CMxab4T0iQxPLCwrg57Qi0sTW1sJhVSygD9ivCfhJwJmD9PNb8bV0rJJ9aWp84LeaC7PDkj5hAozkrrJVA5hozLSXGZb0A4JLKiPOe9ITvxcIqvPNaMPA2SF4AQasE01TeGyuHQICuAMTGFFAP9y0HJBm7N0XmU',
    'trueBooleanValue': true,
    'falseBooleanValue': false,
    'nullBooleanValue': null,
    'simpleObjectValue': {
        'someNumericValue': 123,
        'someStringValue': 'hello there',
        'someNullValue': null,
        'someBooleanValue': false,
    },
    'complexObjectValue': {
        'internalObjectValue': {
            'someNumericValue': 123,
            'someStringValue': 'hello there',
            'someNullValue': null,
            'someBooleanValue': false,
        },
    },
    'superComplexObjectValue': {
        'internalObjectValue': {
            'moreInternalObjectValue': {
                'someNumericValue': 123,
                'someStringValue': 'hello there',
                'someNullValue': null,
                'someBooleanValue': false,
            },
        },
    },
    'typicalObjectValue': {
        'branch_name': 'master',
        'working_dir': '/tmp/whatever',
        'success': true,
    },
    'emptyObjectValue': {},

    'author': {
        'name': 'Alon Diamant',
        'homepage': 'http://www.alondiamant.com',
        'github': {
            'repositories': 12,
            'url': 'http://www.github.com/advance512',
        },
    },
    'company': {
        'name': 'Codefresh',
        'homepage': 'http://www.codefresh.io',
        'phoneNumber': '+972-99-999-9999',
    },
};

The result for the following expressions is:

Available gulp tasks

• gulp lint - runs eslint
• gulp test:unit - runs mocha unit tests
• gulp coverage - runs unit tests and generates coverage report
• gulp test:integration - runs karma tests
• gulp test - runs unit and integration tests and generates code coverage report
• gulp - default task, runs lint and test

Running tests

Install dev dependencies and run the test:

$ npm install -d && gulp

Author

Alon Diamant (advance512)

• github/advance512
• Homepage

License

Copyright © 2016, Codefresh. Released under the MIT license.