Pursuit Dictionary

Pursuit is a fast Object Property Matching Language written for Node. It compiles a given query into JavaScript code for optimal performance when checking many objects for certain characteristics. All compiled functions returns a boolean value, making them useful in filter functions.

This project implements a set of functions used to build Pursuit.

This project is heavily inspired by Mathias Buus's CopenhagenJS talk on JSON query compilation.

Usage

The following usage examples require the pursuit function to be build with Pursuit Core with the following configuration.

var pursuitCore = require('pursuit-core');

var pursuit = pursuitCore({
    dictionary: require('pursuit-dictionary'),
    negation: '!not'
});

Get Pursuit if you just want to use pursuit with the standard configuration.

equals

Will check for equality.

var test = pursuit({
    foo: {
        equals: 5
    }
});

[{foo: 0}, {foo: 5}, {foo: 10}].filter(test); // [{foo: 5}]

Comparison can be done with any type that can be compared using the === operator.

var test = pursuit({
    foo: {
        equals: 'bar'
    }
});

[{foo: 'foo'}, {foo: 'bar'}, {foo: 'baz'}].filter(test); // [{foo: 'bar'}]

greaterThan

Will check if a number (or any other type that can be compared with the > operator) is greater than the compiled value.

var test = pursuit({
    foo: { greaterThan: 5 }
});

[{foo: 0}, {foo: 5}, {foo: 10}].filter(test); // [{foo: 10}]

greaterThanOrEqualTo

Will check if a number (or any other type that can be compared with the >= operator) is greater than, or equal to, the compiled value.

var test = pursuit({
    foo: { greaterThanOrEqualTo: 5 }
});

[{foo: 0}, {foo: 5}, {foo: 10}].filter(test); // [{foo: 5}, {foo: 10}]

lessThan

Will check if a number (or any other type that can be compared with the < operator) is less than the compiled value.

var test = pursuit({
    foo: { lessThan: 5 }
});

[{foo: 0}, {foo: 5}, {foo: 10}].filter(test); // [{foo: 0}]

lessThanOrEqualTo

Will check if a number (or any other type that can be compared with the <= operator) is less than, or equal to, the compiled value.

var test = pursuit({
    foo: { lessThanOrEqualTo: 5 }
});

[{foo: 0}, {foo: 5}, {foo: 10}].filter(test); // [{foo: 0}, {foo: 5}]

contains

Will check if a string contains the given value.

var test = pursuit({
    foo: { contains: 'b' }
});

[{foo: 'abc'}, {foo: 'bac'}, {foo: 'acd'}].filter(test); // [{foo: 'abc'}, {foo: 'bac'}]

beginsWith

Will check if a string begins with the given value.

var test = pursuit({
    foo: { beginsWith: 'ba' }
});

[{foo: 'abc'}, {foo: 'bac'}, {foo: 'acd'}].filter(test); // [{foo: 'bac'}]

endsWith

Will check if a string ends with the given value.

var test = pursuit({
    foo: { endsWith: 'ac' }
});

[{foo: 'abc'}, {foo: 'bac'}, {foo: 'acd'}].filter(test); // [{foo: 'bac'}]

typeOf

Will check if the input is of a certain JavaScript type.

var test = pursuit({
    foo: { typeOf: 'string' }
});

[{foo: 'abc'}, {foo: 5}, {foo: false}].filter(test); // [{foo: 'abc'}]

It can check for the following types: string, number, object, boolean, array, and null.

The test for object does not return true for null values. At the time being object return true for arrays. I do not know if it should stay that way.

isSet

Will check if the key is set to a value (everything but null or undefined) on an object; value can be true for set; and or false for not set.

var test = pursuit({
    foo: { isSet: true },
    bar: { isSet: false }
});


[{foo: 1}, {bar: 2}, {foo: 3, bar: null}].filter(test) // [{foo: 1}, {foo: 3, bar: null}]

Notice, isSet will return true if the set value is set to anything but undefined or null. Falsy values like 0, false and "" (the empty string) will return true.

hasBeenTouched

Will check if a key has been set on an object. It will return true even if the value is set to undefined or null. It will always return true (or false if set to check if a value has not been touched) if the key is the root object:

var test = pursuit({ hasBeenTouched: true });
test(undefined); // true

It is more useful in nested objects.

var test = pursuit({ foo: { hasBeenTouched: true }});
[{foo: null, bar: 1}, { bar: 1 }, {foo: 2}].filter(test); // [{foo: null, bar: 1}, {foo: 2}]

In most cases you would use the isSet function that return true for any value except undefined or null.

Development

After cloning the project you will have to run npm install in the project root. This will install the various grunt plugins and other dependencies.

QA tools

The QA tools rely on the Grunt task runner. To run any of these tools, you will need the grunt-cli installed globally on your system. This is easily done by typing the following in a terminal.

$ npm install grunt-cli -g

The unit tests will need the Buster unit test framework.

$ npm install -g buster

These two commands will install the buster and grunt commands on your system. These can be removed by typing npm uninstall buster -g and npm uninstall grunt-cli -g.

Unit Tests

If you haven't all ready install the Grunt CLI tools and have a look at the grunt configuration file in the root of the project.

When developing you want to run the script watcher. Navigate to the project root and type the following in your terminal.

$ grunt watch:scripts

This will run the jshint and tests each time a file has been modified.

Benchmarks

You can run the benchmarks by running grunt benchmark. This will output some simple benchmarks to *project-root*/benchmark.

The tests use a static data set, data.json, located in the benchmark folder. If you want a bigger data set a new one can be created by changing the number of times the random person generator is run in the random-person.js-file and run it by typing node random-person.js in a terminal.

Notice, these benchmarks are only usable if they are run on the same computer, because it measures the time a task takes. The parameters that could influence this vary from system to system. That said, if you run benchmarks once in a while, while trying to optimize the speed of the library, it should give you some insights. Some insights are better than none.

Generating Documentation

The project uses YUIDocs that can be generated by running grunt docs. This will create a site with documentation in a folder called docs/ in the project root which can be served on port 8888 by typing grunt connect:docs. If you want to generate docs on file modification you can run grunt watch:docs.

License

The MIT License (MIT)

Copyright (c) 2014 Martin Gausby

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.