AngularJS

MEAN.io – Installing in Windows 8.1 (MEAN Stack)

MEAN.io is becoming a Popular Modern Framework for MEAN Stack(Mongo , Express , Angular , Node). I have recently tried it out and had real fun with it , such an awesome Boilerplate for MEAN Stack.

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Most of the Developers around the world work on MAC/LINUX when they are with MEAN. But I thought why not to write a Full Process for Windows Users . Cool , lets do the whole thing to get running an MEAN.io app in Win8.1.

First , We need to install the Core Node And Mongo.

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MongoDB Installation in Windows 8.1

1.Just go to MongoDB Download Center And download like the below picture.

MongoDb

2.Click and Start Installation.

Mongo Install Starts

Mongo Install Starts

3.Do the Complete Installation.

Mongo Complete

Mongo Complete

4.Go to the installed Directory and try to run Mongo Server mongod.exe , You will get exception like below.

Mongo Server mongod.exe

Mongo Server mongod.exe

5.Run the below command in terminal to create those Directories

mkdir c:\data\db
mkdir c:\data\log

6. Now try to run Mongo Server mongod.exe on terminal

C:\Program Files\MongoDB\Server\3.0\bin\mongod.exe

Depending on the security level of your system, Windows may pop up a Security Alert dialog box about blocking “some features” of C:\mongodb\bin\mongod.exe from communicating on networks. All users should select Private Networks, such as my home or work network and click Allow access.

Allow

7.Now run Mongo Client mongo.exe on another terminal

C:\Program Files\MongoDB\Server\3.0\bin\mongo.exe

Mongo Server Client

Mongo Server Client

MongoDB successfully installed.

Now lets install MongoDB as a Windows Service.

8. Now run the 3 below commands in Terminal.

echo logpath=c:\data\log\mongod.log> "C:\Program Files\MongoDB\Server\3.0\mongod.cfg"

echo dbpath=c:\data\db>> "C:\Program Files\MongoDB\Server\3.0\mongod.cfg"

sc.exe create MongoDB binPath= "\"C:\Program Files\MongoDB\Server\3.0\bin\mongod.exe\" --service --config=\"C:\Program Files\MongoDB\Server\3.0\mongod.cfg\"" DisplayName= "MongoDB" start= "auto"

Your Service is ready now.

To get mongo as CLI , add this to Environment Variable.

Mongo CLI

Mongo CLI

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AngularJS, JavaScript

AngularJS One Time Binding Concept

Angular 1.3 added a new feature called One Time Binding . This is definitely an awesome enhancement for performance of an angular app.

We know , If a data changes in angular app, The $digest cycle checks for changes through watchers and gets the new value and renders the view. But if the app gets bigger with so many data , so many bindings , the $$watchers count increases with $digest loop size. Though in a large collection only few data got changed but the whole data gets rendered which is not good for performance.

One-time expressions will stop recalculating once they are stable, which happens after the first digest if the expression result is a non-undefined value

The main purpose of one-time binding expression is to provide a way to create a binding that gets deregistered and frees up resources once the binding is stabilized. Reducing the number of expressions being watched makes the digest loop faster and allows more information to be displayed at the same time.

Lets see how we can do this in angular app.

<div>
        <h1>Angular OneTimeBinding</h1>
        <br />
        <table>
            <tr ng-repeat="profile in profiles">
                <td>
                    {{::profile.Id}}
                </td>
                <td>
                    {{::profile.Name}}
                </td>
                <td>
                    {{::profile.Address}}
                </td>
            </tr>
        </table>
        <br />

        <button ng-click="addProfiles()">addProfiles</button>
        <button ng-click="getWatchers()">getWatchers</button>

        <div>
            <h3>OneTimeBinding Watchers Count :::  {{totalWatchers}}</h3>
        </div>

    </div>

Here I added {{::}} this syntax for One Time Binding.

Lets see our Controller’s code-

app.controller('profileCtrl' , ['$scope' , function($scope){
    console.log('profileCtrl is running...');

    $scope.profiles = [
                    { Id: 1, Name: 'Masoom', Address: 'Dhaka1' },
                    { Id : 2 , Name : 'Talukdar' , Address : 'Dhaka2' },
                    { Id: 3, Name: 'Shahjada', Address: 'Dhaka3' }
    ];

    $scope.addProfiles = function () {
        var id = $scope.profiles.length + 1;
        $scope.profiles.push({ Id: id, Name: 'AAAA' + id, Address: 'Dhaka' + id });
    };

    $scope.getWatchers = function () {
        var watchers = ($scope.$$watchers) ? $scope.$$watchers.length : 0;
        var child = $scope.$$childHead;
        while (child) {
            watchers += (child.$$watchers) ? child.$$watchers.length : 0;
            child = child.$$nextSibling;
        }
        $scope.totalWatchers = watchers;
    };

}]);

Here If we add a new profile by clicking the addProfile Button , it will add a Row , but the Watcher Count will not increase as its One Time Binding But if we remove the OneTimeBinding Syntax , I will increase the count which hampers the performance.

And, if we do not use One Time Binding in Property Level , but in Collection level like below , then If we click and click addProfile button , it will add new item in the collection inside $scope , but the UI will not render the new Items coz we have used OneTimeBinding in the Collection/List Level.

<table>
            <tr ng-repeat="profile in ::profiles">
                <td>
                    {{profile.Id}}
                </td>
                <td>
                    {{profile.Name}}
                </td>
                <td>
                    {{profile.Address}}
                </td>
            </tr>
        </table>

Hope , It helps you.

Cheers

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