arraydb

Use arrays as basic DB tables, and make queries on them

ArrayDB

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

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

[sudo] npm install [-g] arraydb

Use the src/arraydb.js file.

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 

.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 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 });