I start contextualizing. This GitHub repository I made has only one file uploaded to it, a file package.json, which I pulled from a custom web app template I use. That app uses various tools and frameworks, including AngularJS, Bootstrap 3, SASS, etc., and uses Grunt as an automator.

The two relevant aspects for this scenario that I propose are that:

1. NPM is used as a package manager.

2. In the repository there is no file .gitignore, i.e. no file to specify which files/folders are to be ignored by Git . It is crucial for what comes later.

The content of the file package.json, as it appears in the repository , is as follows:

{
  "name": "miproyecto",
  "version": "1.0.0",
  "description": "",
  "main": "Gruntfile.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "grunt": "^1.0.4",
    "grunt-angular-templates": "^1.2.0",
    "grunt-contrib-connect": "^2.1.0",
    "grunt-contrib-copy": "^1.0.0",
    "grunt-contrib-cssmin": "^3.0.0",
    "grunt-contrib-htmlmin": "^3.1.0",
    "grunt-contrib-jshint": "^2.1.0",
    "grunt-contrib-sass": "^1.0.0",
    "grunt-contrib-uglify": "^4.0.1",
    "grunt-contrib-watch": "^1.1.0",
    "grunt-htmlhint": "^0.9.13",
    "grunt-stylelint": "^0.12.0",
    "load-grunt-tasks": "^5.1.0",
    "stylelint": "^11.1.1"
  },
  "dependencies": {
    "@fortawesome/fontawesome-free": "^5.10.2",
    "@uirouter/angularjs": "^1.0.22",
    "angular": "^1.7.8",
    "angular-animate": "^1.7.8",
    "bootstrap": "^3.3.6",
    "jquery": "^3.4.1"
  }
}

Once the repository is cloned, in Visual Studio Code (which is the editor I use), I open a terminal, and then run npm installto install the dependencies.

When the installation of the dependencies is finished, and the generation of the folder node_modules, it strikes me that, from the VSC Git extension (which I have installed), I get the following notification (I put it in image and text):

The git repository at '[local folder where I have the local copy of my repository]' has too many active changes, only a subset of Git features will be enabled. Would you like to add 'node_modules' to .gitignore?

That refers to the volume of active changes that were taking place, and therefore it suggests if I want to include the folder node_modulesin a file .gitignore, which until now, had not been created.

Considering the volume of changes described for GIT, and the weight on the hard drive that the installed dependencies imply, I want to ask:

1. Should I, or should I not, include the folder node_modules, within the folders that Git should ignore?
2. Outside of the volume and weight aspects, what are the advantages and disadvantages of doing it, or not doing it?

Testing AngularJS I found a situation that I would like to know why it happens.

Take a look at the object $scope.filmthat is defined in the controller below:

/* Modelo */
let app = angular.module('myApp', []);

/* Controlador */ 
app.controller('mainCtrl', ['$scope', function($scope){
  /* Film */ 
  $scope.film = {
    titulo: 'Mad Max Fury Road',
    año: 2015
  };
}]);

As is, it is an object with a property tituloand a property año. In the case of the property año, it is defined with the letter ñ .

$scope.film = {
    titulo: 'Mad Max Fury Road',
    año: 2015
};

If I want to use an expression in a view to print the value of the añoobject's property, using the syntax objeto.propiedad...

<!-- Vista -->
<div ng-app="myApp">
    <div ng-controller="mainCtrl">
        <p>{{film.año}}</p>
    </div>
</div>

...I get an error:

Lexer Error: Unexpected next character at columns 6-6 [ñ] in expression [film.año].

Giving me to understand, according to the AngularJS error reference documentation, that the ñ character generates a lexical error in the expression:

Occurs when an expression has a lexical error, for example a malformed number (0.5e-) or an invalid unicode escape.

If, on the other hand, I use the same expression to print the value of the property añousing the syntax objeto['propiedad'], it doesn't cause any problems, and the value of that property is shown to me in the view.

<!-- Vista -->
<div ng-app="myApp">
    <div ng-controller="mainCtrl">
        <p>{{film['año']}}</p> <!-- HTML: 2015 --> 
    </div>
</div>

test snippet

Here you can try it. I commented out the expression that does not give errors.

/* Modelo */
let app = angular.module('myApp', []);

/* Controlador */ 
app.controller('mainCtrl', ['$scope', function($scope){
  $scope.film = {
    title: 'Mad Max Fury Road',
    año: 2015
  };
}]);

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.7.8/angular.min.js"></script>

<!-- Vista -->
<div ng-app="myApp">
  <div ng-controller="mainCtrl">
    <p>{{film.año}}</p>
    
    <!-- <p>{{film['año']}}</p> -->
  </div>
</div>

I could just as well use the syntax objeto['propiedad']to print my property value, or change the property name from añoto annio(or others).

But the point of my question is to know why AngularJS does not allow the use of the letter ñ as part of a property name, using the syntax objeto.propiedadinside an expression.