This styleguide is another take on how to write AngularJS together with ESLint and ES6.

1. Whitespace is FREE
2. Spaces, tabs, and indentation
3. import and export
4. const, let, and var
5. Methods and chaining
6. Functions
7. Modules
8. Routes
9. Controllers
10. Factories and Services
11. Directives

I cannot stress this enough. Adding whistespace is free and it makes your code easier to follow since you can now start grouping snippets of your code into their own mini-blocks.

• Use spaces instead of tabs.
• Use 2 spaces for your indentation.

Why? Tab spacing differs on IDEs and text editors while spaces do not. By using spaces we eliminate that inconsistency.

• Third party imports e.g. node_modules should be at the top-most level of your file followed by local imports separated by a whitespace.
• Constructors must use TitleCase i.e. import MyService from './my-service'.
• There should be a whitespace between your imports and the rest of your code.

// Recommended
import angular from 'angular';
import uiRouter from 'angular-ui-router';

import MyService from './my-service';

// Rest of the code

• const and let declarations must be on the same line as the keyword.
• const declarations should always be higher than let declarations and each group should be separated by a whitespace.
• var has no place in ES6.
• A whitespace should separate your declarations from the rest of your code.

// Recommended

const users = UserSvc.getUsers();

let currentUserCount = 0;

// Rest of the code

// Avoid

const
  users = UserSvc.getUsers();
  
let
  currentUserCount = 0;

// Rest of the code

// Recommended

const admins = AdminSvc.getAdmins(),
  users = UserSvc.getUsers();
  
let currentAdminAcount = 0;
  currentUserCount = 0;

// Rest of the code

// Avoid

const
  admins = AdminSvc.getAdmins(),
  users = UserSvc.getUsers();
  
let 
  currentAdminAcount = 0;
  currentUserCount = 0;

// Rest of the code

Single line declarations should be grouped with similar single line declarations while multi-line declarations should be in their own group. Each group must be separated by a whitespace.

// Recommended

const maxUsers = 100;
  
const defaultGroups = [
    admin,
    manager,
    user
  ];

// Rest of the code

// Avoid

const maxUsers = 100,
  defaultGroups = [
  admin,
  manager,
  user
];

// Rest of the code

Single method calls must be written in a single line.

// Recommended

angular.module('app', []);

// Rest of the code

Chained methods must be in a new line (per method). This provides a clear understanding of what's going on.

// Recommended

angular
  .module('app')
  .controller('MainCtrl', MainCtrl)
  .directive('mainDirective', mainDirective);

// Rest of the code

There should be a space before and after the function declaration and before and after you close that function.

// Recommended

getTotal(key, items) {

  return items.reduce((sum, item) => sum + item[key], 0);

}

// Rest of the code

// Avoid

getTotal(key, items) {
  return items.reduce((sum, item) => sum + item[key], 0);
}

// Rest of the code

// Avoid

getTotal(key, items) {

  return items.reduce((sum, item) => sum + item[key], 0);
}

// Rest of the code

// Avoid

getTotal(key, items) {
  return items.reduce((sum, item) => sum + item[key], 0);
  
}

// Rest of the code

Functions that will handle actions should be considered as events and therefore should be prefixed with on.

// Recommended

function onUserEdit(name) {

  // Block code goes here

}

// Rest of the code

// Avoid

function userEdit(name) {

  // Block code goes here

}

// Rest of the code

Declare modules without a variable. Since we only use one component per file, there is no need to use a variable.

// Recommended

angular.module('app', []);

// Rest of the code

// Avoid

const app = angular.module('app', []);

// Rest of the code

Large applications typically has a lot of views that do different things. Naming your module per view allows you to separate your components depending on where they are being used rather than what they do. By doing this you can then have independent modules that you can easily extract into another repository if it gets too big living in your current repository.

Assume your main application is called app and it has two separate views called admin and user.

• Use dot notation to separate your views and subviews.
• Use a named array for your dependencies. This keeps your angular code lean.

// Recommended
import angular from 'angular';

import admin from './views/admin';
import user from './views/user';

const dependencies = [
  admin,
  user
];

angular.module('app', dependencies);

// Rest of the code

// Avoid
import angular from 'angular';

import admin from './views/admin';
import user from './views/user';

angular.module('app', [
  admin,
  user
]);

// Rest of the code

Use controllerAs syntax every time.

Why? This ultimately helps you avoid using $scope when you bind things to Angular.

Why? This also helps you avoid name collisions and help keep your controllers tidy.

Do not use ng-controller in your HTML files. Either declare your controller and controllerAs in your route or in your directives.

<!-- Avoid -->

<div ng-controller="MainCtrl as vm">

  <!-- Code goes here -->
  
</div>

Controllers should be in TitleCase and suffixed with Ctrl.

Why? This makes it easy to spot when you have a very large application. Having to use Ctrl instead of Controller also makes it easy on the eyes when you are looking for it.

// Recommended

angular
  .module('app')
  .controller('MainCtrl', [
    MainCtrl
  ]);

// Avoid

angular
  .module('app')
  .controller('mainCtrl', [
    mainCtrl
  ]);

// Avoid

angular
  .module('app')
  .controller('main', [
    main
  ]);

// Avoid

angular
  .module('app')
  .controller('MainController', [
    MainController
  ]);

// Recommended

import angular from 'angular';

class MainCtrl {

  /* @ngInject */
  constructor() {

    this.data = data;

  }

}

angular
  .module('app')
  .controller('MainCtrl', MainCtrl);

// Boilerplate

import template from './index.html';

function mainDirective() {
  return {
    restrict: 'E',
    template: template
  };
}

export default angular
  .module('app.mainDirective', [])
  .directive('mainDirective', mainDirective)
  .name;

Use the Arrange-Act-Assert pattern when arranging and formatting code in your unit tests.

Dependency injections must use double underscore notation and must be the same name as their counterpart variables. i.e. $rootScope will be _$rootScope_.

Why? This helps separate your variables between your dependencies.

Each dependency must be in a new line if there is more than one dependency being injected.

Why? This makes it a lot easier to follow when you have more than 2 dependencies.

      inject((
        _$location_,
        _$q_,
        _$rootScope_,
        _$state_
      ) => {});

#Legacy

• Every single file must be wrapped in an IIFE (Immediately-Invoked Function Expression) and have strict mode enabled. This prevents variables and function declarations from leaking outside of your current scope.
• Global variables like angular should be localized.

(() => {

  'use strict';

  const angular = window.angular;
  
})();

1. IIFE, strict mode, and window

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