jListQuery, A Fluent Querying Interface For JSON/JavaScript Lists

Purpose

jListQuery is a library that provides a fluent interface to query JSON/JavaScript lists/arrays in memory.

Implementation

jListQuery is implemented as a jQuery plugin. You can download the plugin for your own use.

You can include jListQuery in your html file from googlecode by adding the below script tag to your page:

<script src="https://code.google.com/p/jlistquery/source/browse/trunk/jListQuery.js" type="text/javascript"></script>

In ASP .NET MVC 4 view:

@section
Scripts {
@Scripts.Render("https://code.google.com/p/jlistquery/source/browse/trunk/jListQuery.js")
}

A demo of the plugin is on JSFiddle:

http://jsfiddle.net/7B932/2/

The plugin has been hosted by the jQuery Plugin Registry at:

http://plugins.jquery.com/tag/jlistquery/

API	Description	Parameters
list	Initialize the querying interface with a JSON/JavaScript list.	list: the list to initialize with
join	Join another list with exisiting list or previous join.	list: list to join with on: function with the condition of the join
forEach	Iterates through list and executes an action against each item.	action: the action to execute for each element in the list
firstOrDefault	Fetches the first item that matches the predicate or returns null.	predicate: function with the condition
lastOrDefault	Fetches the last item that matches the predicate or returns null.	predicate: function with the condition
singleOrDefault	Fetches the item if it is the only item in the list that matches the predicate or returns null.	predicate: function with the condition
where	Fetches all items from the list that match the predicate.	predicate: function with the condition
toList	Re-initialize the result of a query to a new list or return the result of the previous query. This is to be used with the where and orderBy APIs.	reinitialize: boolean, true initializes a new list and false returns the result.
orderBy	Orders the list by a predicate.	predicate: function with the condition for ordering
select	Returns a list of elements that are the result of the query.	predicate: function that returns a new element
removeAll	Removes all elements that match the predicate.	predicate: function with the condition

Samples

//Json Data

var listEmployees = { "employees": [{ "Id": 3, "Name": "David" }, { "Id": 2, "Name": "Adam" }, { "Id": 1, "Name": "Shan"}] };

var listSuper = { "funds": [{ "EmpId": 3, "FundName": "123 Super" }, { "EmpId": 2, "FundName": "XYZ Super" }, { "EmpId": 1, "FundName": "ABC Super"}] };

var listDetails = { "details": [{ "EmpId": 3, "Address": "123 Street", "Dob": "1995/07/21" }, { "EmpId": 1, "Address": "ABC Street", "Dob": "1983/06/21" }, { "EmpId": 2, "Address": "XYZ Street", "Dob": "1995/06/21"}] };

//Initialize list

$.list(listEmployees.employees);

//Query list

var employee = $.singleOrDefault(function (e) { return e.Name == "Adam"; });

alert(employee.Name);

employee = $.firstOrDefault(function (e) { return e.Name == "Shan"; });

alert(employee.Name);

//Loop through all elements of the list

$.forEach(function (e, index) { alert(e.Name); });

Loop

//Query to get all employees where the Id is greater than or equal to 2

var employees = $.list(listEmployees.employees)

.where(function (e) { return e.Id >= 2 }).toList(false);

for (var i = 0; i < employees.length; i++) {

alert(employees[i].Id + "," + employees[i].Name);

}

//Query to get all employees where the Id is greater than or equal to 2, ordered by Name

var employees = $.list(listEmployees.employees)

.where(function (e) { return e.Id >= 2 }).toList(true)

.orderBy(function (a, b) { return a.Name < b.Name ? -1 : a.Name > b.Name ? 1 : 0; })

.toList(false);

for (var i = 0; i < employees.length; i++) {

alert(employees[i].Id + "," + employees[i].Name);

}

//Query to get all employees (and their details) whose Date of Birth is greater than 1990/01/01, ordered by Name

var employees =

$.list(listEmployees.employees)

.join(listSuper.funds, function (emp, superAnn) { return emp.Id == superAnn.EmpId; })

.join(listDetails.details, function (lastJoin, detail) { return lastJoin[0].Id == detail.EmpId; })

.where(function (joinedItem) { return new Date(joinedItem[2].Dob) > new Date(1990, 1, 1) })

.toList(true)

.orderBy(function (a, b) { return a[0].Name < b[0].Name ? -1 : a[0].Name > b[0].Name ? 1 : 0; })

.select(function (joinedItem) {

var item = {};

item.Id = joinedItem[0].Id;

item.Name = joinedItem[0].Name;

item.Super = joinedItem[1].FundName;

item.Address = joinedItem[2].Address;

item.Dob = joinedItem[2].Dob;

return item;

});

for (var i = 0; i < employees.length; i++) {

alert(employees[i].Id + "," + employees[i].Name + "," + employees[i].Super + "," + employees[i].Address + "," + employees[i].Dob);

}

//Remove all employees whose name matches Adam

$.list(employees)

.removeAll(function (emp) { return emp.Name == "Adam"; });

for (var i = 0; i < employees.length; i++) {

alert(employees[i].Id + "," + employees[i].Name + "," + employees[i].Super + "," + employees[i].Address + "," + employees[i].Dob);

}