ArrayDB

Use your arrays as DB tables, and make queries on them.

Install

This library was mostly written for the client-side, but it’s available as a nppm package.

Node.js

[sudo] npm install [-g] arraydb

Client-side

Use the src/arraydb.js file.

Usage

ArrayDB objects expose one method, .query, which use pattern-matching:

var ArrayDB = require( 'arraydb' ).ArrayDB;

var a = new ArrayDB([

    { name: "Foo", age: 42 },
    { name: "Bar", age: 24 },
    { name: "Moo", age: 42 }

]);

a.query({ age: 42 }); // [ { name:"Foo", age:42 }, { name:"Moo",age:42} ]

It takes an object with the key below:

• query [Anything]: The query. Can be any JS value.
• limit [Number]: Optional (default to Infinity).
• offset [Number]: Optional (default to 0).
• reverse [Boolean]: Optional (default to false). Reverse the query.
• strict [Boolean]: Optional (default to true). Define the matching mode of the query (see below).

You can also monkey-patch Array objects:

var ArrayDB = require( 'arraydb' ).ArrayDB;

ArrayDB.monkeyPatch();

typeof [].query === 'function'; // true

Strict mode

.query works in strict mode by default. In this mode, objects have to be strictly equal to be matched. You can specify the mode using an object:

var a = new ArrayDB( NaN, 'foo' );

a.query({ query: NaN }); // [ NaN ]
a.query({ query: NaN, strict: true }); // [ NaN ]
a.query({ query: NaN, strict: false }); // [ NaN, 'foo' ]

Non-Strict mode

Non-strict mode provide some helpers to match elements:

• Regexps can be used to test strings
• Functions can be used to test anything
• Booleans match truthy (and falsy) elements
• NaN match any non-number (where isNaN(element) is true)

var a = new ArrayDB(
    { age: 2, name: "Bar" },
    { age: 46, name: "Foo" },
    { name: "NoAge" }
);

// returns only objects with an `age` property
a.query({ query: { age: true }, strict: false });

// returns only names that start with "F"
a.query({ query: { name: /^F/ }, strict: false });

Also, ArrayDB provides some helpers:

• .lt( e ): match elements lesser than e
• .gt( e ): match elements greater than e
• .le( e ): match elements lesser than, or equal to e
• .ge( e ): match elements greater than, or equal to e
• .eq( e ): match elements equal to e
• .ne( e ): match elements that are not equal to e
• .any(): match anything

var a = new ArrayDB(
    { name: "John Doe", age: 23 },
    { name: "Foo Bar", age: 12 },
    { name: "Bar Foo", age: 35 },
    { name: "Bar Moo", age: 42  }
);

// match only objects with a .age property greater than 18
a.query({ query: { age: ArrayDB.gt( 18 ) }, strict: false });

// match only objects with an .age property equal to 42
a.query({ query: { age: ArrayDB.eq( 42 ) }, strict: false });