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: 
  1. <script src="https://code.google.com/p/jlistquery/source/browse/trunk/jListQuery.js" type="text/javascript"></script>   
In ASP .NET MVC 4 view: 
  1. @section  
  2. Scripts {  
  3.     @Scripts.Render("https://code.google.com/p/jlistquery/source/browse/trunk/jListQuery.js")  
  4. }   
A demo of the plugin is on JSFiddle:
 
 
The plugin has been hosted by the jQuery Plugin Registry at:
 
  
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);

 
Json List 

 

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

    alert(employee.Name);

 
Query list 

 

    //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);

    }

For loop in list 

 

  //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);

    }

 
 Query to get all employees
 
     //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);

    }

 
Remove all employees 

X

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