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objeq (JavaScript Object Querying)

Introduction

objeq is a simple library that allows POJSO's (Plain-Old JavaScript Objects) to be queried in real-time.

What Does it Do?

It lets you take a JavaScript Array and query it. Querying includes one or more steps of filtering, drill-down, synthesis, sorting and/or aggregation. It also optionally allows you to generate dynamic results, such that if anything in the original Array changes, the query result will immediately reflect those changes.

What Doesn't it Do?

Everything else.

Current Status

The grammar is now frozen but the query engine is still under active development Performance will continue to improve. Note that objeq relies on JavaScript property setters to provide some of its functionality, and so it will only work in more recent browsers and JavaScript environments.

Getting Started

Getting started is so frickin' easy!

Installation

A pre-built version of the parser and minified code are already included, but if you'd like to build them yourself and you have node.js, then you can do so by issuing the following command from the package's top-level directory:

> npm install; npm run-script build

This will also install any development dependencies and run the nodeunit test suite.

Inclusion in a Web Page

You can include the objeq Library on your web page with the following HTML:

<script src="objeq.min.js" type="text/javascript"></script>

You can also include the unminified parser and processor with the following:

<script src="objeq/objeq-parser.js" type="text/javascript"></script>
<script src="objeq/objeq.js" type="text/javascript"></script>

Inclusion in Node.js

Assuming you have installed the objeq Library into your project with npm, you can include it in a node.js module with the following:

var $objeq = require('objeq');

Performing a First Query

Assuming you have node.js installed, you can fire up the REPL and type the following into the console (minus comments):

// Import the objeq Library
var $objeq = require('objeq');

// Create a data Array to be queried later
var data = [
  { name: 'Barbara', age: 25, gender: 'female' },
  { name: 'Ronald', age: 62, gender: 'male' },
  { name: 'Robert', age: 54, gender: 'male' },
  { name: 'Jessica', age: 48, gender: 'female' }
];

// This will compile an objeq query that filters only those
// Objects having a name property starting with 'Ro' and then
// returns a string that combines name and age properties
var query = $objeq("'^Ro' =~ name -> name + ' is ' + age");

// This performs the query against the 'data' Array and
// returns the result in 'res'
var res = query(data);

// --> res now contains:
//  [ 'Ronald is 62 years old',
//    'Robert is 54 years old' ]

If you don't have node.js installed, you can instead open the Query Tester in your browser. It is located in the Examples directory at examples/index.html

More Information

For more information about how to interact with the objeq Library and its single API function, see the API Reference at doc/API-Reference.md

For more information about the objeq Query Language itself, including its syntax and grammar, see the Language Reference at doc/Language-Reference.md

Credits and Acknowledgements

This module defines both a Lexer and Grammar that use the Jison Parser Generator (http://zaach.github.com/jison/)

License (MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.