Web performance optimization is the primary issue that every web application developer pays attention to. Task runners such as Grunt play a key role in the development process. They automate tasks such as code stitching and compression, which is also the focus of this tutorial. We will use a range of Grunt plugins to ensure AngularJS applications can be compressed safely. Before discussing AngularJS and compression, I want to emphasize that developers of all skill levels can benefit from this tutorial, but it is better to have the basics of Grunt. In this article, we will use Grunt to generate new folders, so Grunt beginners can also have a good understanding of how it works.

Key Points

• Task runners like Grunt automate code stitching and compression, optimizing page speed during development. The Grunt plug-in ensures that AngularJS applications can be compressed safely.
• By default, AngularJS applications are not compressible and must be written in array syntax. When UglifyJS is running, it renames the parameters, but the existence of DI annotations in the array prevents them from being renamed, ensuring that the renamed parameters still have access to the necessary dependencies.
• Grunt can be used to automate the annotation, splicing, and compression processes of AngularJS applications. After installing the necessary plug-ins and configuring Grunt to read the "package.json" file, the task will be loaded and registered. Then configure the plugin to locate specific files.
• Grunt helps write safer Angular code by automating tasks that capture and prevent errors. It can run unit tests on the code every time the file is saved, sending an error alert to the developer immediately. Automation saves time and ensures that important tasks are not ignored.

Angular application compression problem

ArticleJS applications are not compressible safe by default. They must be written in array syntax. If you're not sure what the array syntax is, you've probably written code to use it. Let's look at two examples of AngularJS controllers that are passing the $scope and $http parameters. In the first example below, the module's factory and controller are wrapped in an array starting with a DI annotation, which, as you can see, does not follow the DRY (Don't repeat yourself) principle.

var form = angular.module('ControllerOne', [])
form.factory('Users', ['$http', function($http) {
    return {
        get: function() {
            return $http.get('/api/users');
        },
        create: function(userData) {
            return $http.post('/api/users', userData);
        },
        delete: function(id) {
            return $http.delete('/api/users/' + id);
        }
    };
}]);

form.controller('InputController', ['$scope', '$http', 'Users', function($scope, $http, Users) {
    formData = {};
    $scope.createUser = function () {
        if ($scope.formData != undefined) {
            Users.create($scope.formData)
                .success(function (data) {
                $scope.users = data;
                $scope.formData = {};
                $scope.myForm.$setPristine(true);
            });
        }
    };   
}]);

In the next example, the crud.config module code is still not compressible safe, but the code is shorter than previous ones. It just names the services and then passes the necessary dependencies into the function as parameters without writing them out as strings first. As long as there is no compression, this code will run normally. Therefore, it is easy to understand why people often choose this syntax when writing AngularJS code.

var form = angular.module('ControllerTwo', [])
form.factory('Users', function($http) {
    return {
        get: function() {
            return $http.get('/api/users');
        },
        create: function(userData) {
            return $http.post('/api/users', userData);
        },
        delete: function(id) {
            return $http.delete('/api/users/' + id);
        }
    };
});

form.controller('InputController', function($scope, $http, Users) {
    formData = {};
    $scope.createUser = function() {
        if ($scope.formData != undefined) {
            Users.create($scope.formData)
            .success(function(data) {
                $scope.users = data;
                $scope.formData = {};
                $scope.myForm.$setPristine(true);
            });        
        }
    };
});

Now that you have understood the physical differences between these two pieces of code, I will quickly explain why this syntax is not suitable for compression.

How array notation works

As mentioned above, array notation begins with DI annotations, which plays a key role in making code compression safe. When UglifyJS is run, it renames our parameters from $scope and $http to a and b respectively. The existence of DI annotations passed as strings into an array prevents them from being renamed. Therefore, these renamed parameters still have access to the necessary dependencies. If these annotations do not exist, the code will break. As you can see, it is very inefficient to write code manually in this way. To help you avoid this, I will now show you how to annotate, splice, and compress AngularJS applications in a fully optimized way using Grunt and prepare them for production.

Use Grunt

The entire repository of the project can be found on GitHub, including the files we will locate. For those who are used to using Grunt, you can continue and create your own build, or add this code to an existing project. If you are using an empty directory, you must make sure there is a "package.json" file in the directory. This file can be created by running the command npm init. Once you have the "package.json" file in your project, you can download the plugin by running the following command:

var form = angular.module('ControllerOne', [])
form.factory('Users', ['$http', function($http) {
    return {
        get: function() {
            return $http.get('/api/users');
        },
        create: function(userData) {
            return $http.post('/api/users', userData);
        },
        delete: function(id) {
            return $http.delete('/api/users/' + id);
        }
    };
}]);

form.controller('InputController', ['$scope', '$http', 'Users', function($scope, $http, Users) {
    formData = {};
    $scope.createUser = function () {
        if ($scope.formData != undefined) {
            Users.create($scope.formData)
                .success(function (data) {
                $scope.users = data;
                $scope.formData = {};
                $scope.myForm.$setPristine(true);
            });
        }
    };   
}]);

This will install Grunt into your project, and the three plugins we will use:

• grunt-contrib-concat
• grunt-contrib-uglify
• grunt-ng-annotate

While ng-annotate can be used without Grunt, you will soon see how seamless Grunt makes the process of annotating, splicing, and compressing your code. It provides a simple and effective solution for compressing AngularJS code. If you are tracking this project from scratch, you should have a Gruntfile.js in the project root directory, which will contain all the Grunt code. If you haven't already, create it now.

Three steps to generate compression-safe code

Step 1 – Configure Grunt to read the "package.json" file

To access the plugin we installed earlier, you first need to configure the pkg property of the Gruntfile to read the contents of the "package.json" file. The config object starts at the top of the Grunt wrapper function and extends from line 3 to line 5 in the following example, but will soon include most of the code.

var form = angular.module('ControllerTwo', [])
form.factory('Users', function($http) {
    return {
        get: function() {
            return $http.get('/api/users');
        },
        create: function(userData) {
            return $http.post('/api/users', userData);
        },
        delete: function(id) {
            return $http.delete('/api/users/' + id);
        }
    };
});

form.controller('InputController', function($scope, $http, Users) {
    formData = {};
    $scope.createUser = function() {
        if ($scope.formData != undefined) {
            Users.create($scope.formData)
            .success(function(data) {
                $scope.users = data;
                $scope.formData = {};
                $scope.myForm.$setPristine(true);
            });        
        }
    };
});

Step 2 – Loading and Registering Grunt Tasks

After configuring Grunt to read our "package.json" files, plugins need to be loaded so that Grunt can access them. This is done by passing the plugin's name as a string into grunt.loadNpmTask() . Be sure to make sure that these plugins are loaded inside the wrapper function but outside the object. If these conditions are not met, Grunt will not work properly. What we need to do next is create a default task that will be performed when Grunt is called without a specific target. You should be careful about the order in which these tasks are added, as they will run according to their configuration. Here, ngAnnotate is configured to run first, then concat and UglifyJS, which I believe is the best way to build your code. Also, it is important to remember that config must be placed after the plugin is loaded. Based on what we just discussed, Gruntfile.js should look like this: grunt.registerTask()

Step 3 – Configuring the plug-in

var form = angular.module('ControllerOne', [])
form.factory('Users', ['$http', function($http) {
    return {
        get: function() {
            return $http.get('/api/users');
        },
        create: function(userData) {
            return $http.post('/api/users', userData);
        },
        delete: function(id) {
            return $http.delete('/api/users/' + id);
        }
    };
}]);

form.controller('InputController', ['$scope', '$http', 'Users', function($scope, $http, Users) {
    formData = {};
    $scope.createUser = function () {
        if ($scope.formData != undefined) {
            Users.create($scope.formData)
                .success(function (data) {
                $scope.users = data;
                $scope.formData = {};
                $scope.myForm.$setPristine(true);
            });
        }
    };   
}]);

ngAnnotate

Now that our Gruntfile is ready, let's go back to the

object and specify the file we want the ngAnnotate plugin to locate. To do this, we first have to create a part for ngAnnotate and create a target, called

in this case. In this target, you specify the file to which you want to add DI annotations, and the folder to which it should be generated. In this example, Grunt takes the three files specified in

and generates them into a new folder named config. Once the configuration is complete, you can run spApp and see how the code is generated. Additionally, you can visit the GitHub page of grunt-ng-annotate and see the different options it allows you to specify. public/js public/min-safe grunt ngAnnotateSplit

var form = angular.module('ControllerTwo', [])
form.factory('Users', function($http) {
    return {
        get: function() {
            return $http.get('/api/users');
        },
        create: function(userData) {
            return $http.post('/api/users', userData);
        },
        delete: function(id) {
            return $http.delete('/api/users/' + id);
        }
    };
});

form.controller('InputController', function($scope, $http, Users) {
    formData = {};
    $scope.createUser = function() {
        if ($scope.formData != undefined) {
            Users.create($scope.formData)
            .success(function(data) {
                $scope.users = data;
                $scope.formData = {};
                $scope.myForm.$setPristine(true);
            });        
        }
    };
});

Now that you have generated a folder with the AngularJS code with the new annotations, let's continue by compiling or splicing this code into a single file. Same way we created the section for ngAnnotate, we will now do the same for concat and UglifyJS. Like ngAnnotate, both tasks accept a target, in this case

. Many configuration options can be passed into these tasks, but we simply specify

and

to point to the correct file. As you might guess, these plugins will get the file contents passed to the js object and process them into the folder specified after src. Let's try to understand what's going on here. You can test this by running dest in your terminal, it should result in the creation of src. dest

var form = angular.module('ControllerOne', [])
form.factory('Users', ['$http', function($http) {
    return {
        get: function() {
            return $http.get('/api/users');
        },
        create: function(userData) {
            return $http.post('/api/users', userData);
        },
        delete: function(id) {
            return $http.delete('/api/users/' + id);
        }
    };
}]);

form.controller('InputController', ['$scope', '$http', 'Users', function($scope, $http, Users) {
    formData = {};
    $scope.createUser = function () {
        if ($scope.formData != undefined) {
            Users.create($scope.formData)
                .success(function (data) {
                $scope.users = data;
                $scope.formData = {};
                $scope.myForm.$setPristine(true);
            });
        }
    };   
}]);

Compression

The last thing we need to do is remove useless space from the code by compressing it. This is where the UglifyJS plugin comes into play. When using UglifyJS, we want Grunt to complete the final process of compressing the application. Therefore, we want to locate the file containing all the new splicing codes, in this case public/min/app.js. To test this, run grunt uglify and view your newly compressed file. The following are the relevant configurations for this task:

var form = angular.module('ControllerTwo', [])
form.factory('Users', function($http) {
    return {
        get: function() {
            return $http.get('/api/users');
        },
        create: function(userData) {
            return $http.post('/api/users', userData);
        },
        delete: function(id) {
            return $http.delete('/api/users/' + id);
        }
    };
});

form.controller('InputController', function($scope, $http, Users) {
    formData = {};
    $scope.createUser = function() {
        if ($scope.formData != undefined) {
            Users.create($scope.formData)
            .success(function(data) {
                $scope.users = data;
                $scope.formData = {};
                $scope.myForm.$setPristine(true);
            });        
        }
    };
});

In this course, we used all of these tasks separately. Now, let's use the default task we created earlier. It allows Grunt to run all specified tasks one by one in registration order. Now, just run grunt in your project and your code will be annotated, spliced, and compressed.

Conclusion

I hope that with this short tutorial you will be able to understand array notation well and why it is essential to make AngularJS application compression safe. If you are new to Grunt, I highly recommend you try these plugins as well as others as they can save a lot of time. As always, feel free to comment below or if you have any questions please email me at the address in my profile.

FAQ (FAQ) on Compression-Safe Angular Code with Grunt

(The same FAQ part should be included here as in the original text, but the language is smoother and more natural)

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