JavaScript's 9 Native Object Constructors

In JavaScript almost everything is object or act like object. Most values (excluding primitive values) involve object being created or instantiated from constructor function. An object returned from the constructor is called an instance. JavaScript uses native constructor to build everything.

JavaScript has nine native constructors to achieve everything in JavaScript programming language. For example functions are objects created from Function() constructor. String(), Boolean() and Number() constructors are not only construct objects but also provide primitive value for string, Boolean, and number.

• String()
• Boolean()
• Number()
• Object()
• Function()
• Array()
• RegExp()
• Error()
• Date()

To remember these 9 native constructors I have created one acronym "SBN OF A RED". This acronym is easy to learn and also in relevant groups.

To create a number variable in JavaScript there are 2 ways:

1. var iMyNumberPrimitive = 9;
2. var iMyNumberObject = new Number(9);

First method is to just create primitive value for number, string or Boolean. Second method create complex object with primitive value. You can see below the behavior of such declarations with console:

Same way we can create other type of variables also. It is good practice to use simple primitive variable declaration always if we want normal variables operations, because JavaScript create complex object when you use constructor and will have many other properties associated with variable.

To Do list App with Angular JS (Learn basic concepts of Angular JS)

Hello All,

Angular JS is really awesome framework created by Google, I learn just basic concepts of Angular JS from codeschool and able to create this application. This small application is a To Do list to keep track of your tasks. I created this for only running session, there is no permanent storage of tasks information.

The HTML code used for Tasks App:

        

            Total Tasks: {{TaskCtrl.taskCounter}}
            Tasks Pending: {{TaskCtrl.taskPendingCounter}}
            Tasks Done: {{TaskCtrl.taskDoneCounter}}
            

                Task title:
                

                Task description:
                
                

                
Add Task
            
            

            
        
    

In Angular JS we can have any number of template file which can be included any where in HTML code using "ng-include" directive of Angular JS, Template file for task "TaskTemplate.html" is as shown below:

    {{task.title}}: 
    {{task.description}}
    
Done?
    
    

JavaScript file to create controller for Tasks App is as shown below:

(function () {
    var TaskApp = angular.module("TaskApp", []);
    var Tasks = {
        TasksDetail: [
            {
                id: 1,
                title: "Sample Task 1",
                description: "GO for Aadhar card on Saturday",
                isDone: true
            },
            {
                id: 2,
                title: "Sample Tasks 2",
                description: "Go to shopping in InOrbit on Sunday to buy jeans",
                isDone: false
            }
        ],
        TaskStarted: "Today"
    };

    TaskApp.controller("TaskController", function () {
        this.tasks = Tasks.TasksDetail;
        this.addTask = function (taskTitle, taskDetail) {
            if (!!taskTitle) {
                var task = {
                    id: this.tasks.length + 1,
                    title: taskTitle,
                    description: taskDetail,
                    isDone:false
                }
                this.tasks.push(task);
                this.updateCounter();
                this.taskTitle = "";
                this.taskDesc = "";
            } else {
                alert("Enter title");
            }
        };
        this.removeTask = function (taskId) {
            if (confirm("Task will be deleted..!")) {
                this.tasks.splice(this.getTasksIndex(taskId), 1);
                this.updateCounter();
            }
        };
        this.doneTask = function (taskId,bFlag) {
            this.tasks[this.getTasksIndex(taskId)].isDone = bFlag;
            this.updateCounter();
        };

        this.getTasksIndex = function (taskId) {
            var index = 0;
            for (index = 0; index < this.tasks.length; index++) {
                if (this.tasks[index].id == taskId) {
                    return index;
                }
            }
            return -1;
        };
        this.getTasksCounter = function (isDoneFlag) {
            var counter = 0, index = 0;
            for (index = 0; index < this.tasks.length; index++) {
                if (this.tasks[index].isDone === isDoneFlag) {
                    counter++;
                }
            }
            return counter;
        };
        this.updateCounter = function () {
            this.taskPendingCounter = this.getTasksCounter(false);
            this.taskDoneCounter = this.getTasksCounter(true);
            this.taskCounter = Tasks.TasksDetail.length;
        };
        this.updateCounter();
    });
})();

You can use the app which I have hosted here, you can try to add new tasks, try to complete the taks and delete the tasks:

Style on app is from customized CSS file, you can update CSS properties to update UI/UX. My CSS file is as shown below:

body {
    background-color: #1ec885;
    font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande', 'Lucida Sans Unicode', Geneva, Verdana, sans-serif;
    color: white;
}

#TaskForm {
    color: white;
}

.Box {
    width: 150px;
    height: 20px;
    display: inline-block;
    margin-top: 5px;
}

.InputTextBox {
    width: 100%;
    border-radius: 4px;
}

.InputTextBoxDescription {
    height: 35px;
}

.Button {
    text-align: center;
    cursor: pointer;
}

.ImageButton {
    vertical-align: middle;
}

.AddButton {
    background-color: #ff6a00;
    width: 200px;
    height: 30px;
    padding-top: 10px;
}

.RemoveButton {
    background-color: #961616;
    width: 20px;
    display: inline-block;
    height: 17px;
}

.DoneButton {
    background-color: #ff6a00;
    width: 50px;
}

#TaskFormTable {
    width: 100%;
}

.TaskItem {
    margin: 5px;
}

.TaskTitle {
    font-weight: 900;
}

Shrink transaction Log using linked server 3 part naming

Many times transaction log space gets full on SQL servers. To truncate transaction log we can use below script:

 DECLARE @Query NVARCHAR(1000)
 SET @Query = N'DBCC SHRINKFILE(2,0,''TRUNCATEONLY'')'
 EXEC YourServerName.YourDBName.dbo.sp_executesql
 @statement = @Query

DBCC is database console command, 2 in SHRINKFILE signifies log file.