query.js

Introduction

query.js is an abstract query language which can be mapped to different query language implementations. It runs in the browser as well as on Node.js.

Installation

On Node.js include the query module.

var query = require("query").query;
var myQuery = query().eql("foo",3);

For use in the browser include the query.js file.

<script src="lib/query.js" type="text/javascript"></script> 

Javascript Module

To create a new query instance you have two options:

var query = query();
var query2 = new Query();

SORTING

Sorting ascending by name:

var q = query()
            .sort("name");

Sorting descending by name:

var q = query()
            .sort("-name");

Sorting over more than one field (short written):

var q = query()
            .sort("name", "-firstname", "+birthday");

Sorting over more than one field (long written):

var q = query()
            .sort([{
                field: "xyz"
            }, {
                field: "abc",
                direction: -1
            }]);

COMPARISON operator

Comparison operators are by default concatinated with ANDs.

var q = query()
          .eql("name", "tony")
          .gt("age", 18);

NOT operator

var q = query()
          .not(function (where) {
              where
                  .eql("name", "tony")
          });

OR operator

var q = query()
          .or(function () {
              this.eql("name", "tony")
          }, function () {
              this.eql("name", "marcus")
          });

AND operator

var q = query()
          .and(function () {
              this.eql("name", "tony")
          }, function () {
              this.eql("name", "marcus")
          });

Array query executor

The ArrayExecutor allows you to execute the query on an array of items.

var items = [
    {
        name: "Adam",
        age: 18,
        address: {
            city: "New York"
        }
    },
    {
        name: "Bob",
        age: 20
    },
    {
        name: "Charlie",
        age: 10
    }
];

var q = query().eql("name", "Adam");

var filterItems = ArrayExecutor.filterItems(q,items);

/* output: [{
        name: "Adam",
        age: 18,
        address: {
            city: "New York"
        }
    }] */

Query Parsers

• REST query parser - parses a REST query string to a query object

Query Composers

The project includes the following query composers:

• REST query composer - composes the query to a REST query string
• MongoDB query composer - composes the query to a MongoDB JSON query format