JQ

JQ is a DSL for querying javascript object. APIs are very similar to jQuery. If you know jQuery, you can use this library immediately.

Installation

via npm:

$ npm install JQ

Browser Support

To compile JQ to a single file runnable for client-side use simply execute:

$ make JQ.js

Example

var JQ = require('JQ').JQ;

var family = {
  father_name: 'bob',
  mother_name: 'kathy',
  children: [
    { 
      name: 'john',
      age: 3
    },
    {
      name: 'alice',
      age: 2
    },
    {
      name: 'mike',
      age: 1
    }
  ]
};

var $family = JQ(family);
$family("name === 'john' || age === 1").get(0); // -> { name: 'john', age: 3 }
$family("name === 'john' || age === 1").get(1); // -> { name: 'make', age: 1 }
$family("father_name === 'bob'").get(0).mother_name; // -> 'kathy'

API

JQ(object), JQ(string)

Produces a selector object which take condition expression. JQ take a javascript object or string which can be parsed as JSON.

var JQ = require('JQ').JQ;
var people = {
  [
    {
      name: 'john'
    },
    {
      name: 'bob'
    }
  ]
};
var $people = JQ(people);
// or
var $people = JQ('{ [ { "name": "john" }, { "name": "bob" } ] }');

Selectors

Selector accepts a conditional expression to filtering object. In a conditional expression, you can use operators below.

• .(member)
• [](member)
• !
• ~
• typeof
• /
• %
• <<
• <
• <=

• =

• in
• instanceof
• ==
• !=
• ===
• !==
• =~ (JQ original!)
• !~ (JQ original!)
• &
• ^
• |
• &&
• ||
• ?:

Detail of each operators is on MDN(https://developer.mozilla.org/en/JavaScript/Reference/Operators/Operator_Precedence), but [=], [!] operators are JQ original. these are inspired by perl and ruby. You can use these operators for regex matching. If you want to change operators precedence, you can use a parenthesis of course.

var messages = [
  {
    speaker: 'bob',
    message: 'hello'
  },
  {
    speaker: 'john',
    message: 'hello'
  },
  {
    speaker: 'bob',
    message: 'good bye'
  },
  {
    speaker: 'bob',
    message: 'see you again'
  }
];

var $messages = JQ(messages);
$messages('speaker === "bob" && ( message === "hello" || message === "good bye")');

baseObject

Return a object which is passed to JQ first.

var obj = { name: "bob", age: 18};
$obj = JQ(obj);
$obj.baseObject === obj // -> true

size

Return the number of elements in JQ object.

var people = [{ name: "bob" }, { name: "jack" }, { name: "alice" }];
var $people = JQ(people);
$people.size() // -> 1
$people('name === "bob" || name === "alice"').size() // -> 2

get

Return the nth object in the matched object set

var people = [{ name: "bob" }, { name: "jack" }, { name: "alice" }];
var $people = JQ(people);
$people('name === "bob" || name === "alice"').get() //-> [{ name: "bob" }, { name: "alice" }]
$people('name === "bob" || name === "alice"').get(0) //-> { name: "bob" }
$people('name === "bob" || name === "alice"').get(1) //-> { name: "alice" }

eq

Return the new JQ object that only have the nth object in the matched object set

var people = [{ name: "bob" }, { name: "jack" }, { name: "alice" }];
var $people = JQ(people);
$people('name === "bob" || name === "alice"').eq(1).get(0) //-> { name: "bob" }

empty

Remove all properties from the matched object set.

var people = [{ name: "bob" }, { name: "jack" }, { name: "alice" }];
var $people = JQ(people);
$people('name === "bob" || name === "alice"').empty().get() //-> [{}, {}]
$people //-> [{}, {name: "jack" }, {}]

prop

Return value of a property for the first object in the matched object set

var people = [{ name: "bob" }, { name: "jack" }, { name: "alice" }];
var $people = JQ(people);
$people('name === "bob" || name === "alice"').prop("name") //-> "bob"
$people('name === "bob" || name === "alice"').eq(1).prop("name") //-> "jack"

remove

removeProp

each

map