ngMeta

Dynamic meta tags in your AngularJS single page application

This is an Angular 1.x module. Angular2 module is available as ng2-meta

• Demo
• Install
• Getting Started
• Defaults
• Dynamic meta tags
• Debugging
• Advanced
  • Data inheritance in ui-router
  • Using custom data resolved by ui-router
  • Support for other crawlers
• Websites using ngMeta
• Further reading
• Licence

Demo

vinaygopinath.github.io/ngMeta

Install

via NPM:

npm install ng-meta --save

via Bower:

bower install ngMeta --save

via CDN:

https://cdnjs.cloudflare.com/ajax/libs/ng-meta/1.0.3/ngMeta.min.js

or download the file from dist.

Getting started

1. Add ngMeta as a dependency of your module. ngMeta supports ui-router and ngRoute.

   angular.module('YourApp',['ngMeta']);

2. Add meta objects to your routes (ngRoute) or states (ui-router) and specify the meta tags appropriate to each view. Other than title and titleSuffix, which are reserved properties that affect the title of the page, the tag properties can be named as per your choice.

   .config(function ($routeProvider, ngMetaProvider) {
    
     $routeProvider
     .when('/home', {
       templateUrl: 'home-template.html',
       data: {
         meta: {
           'title': 'Home page',
           'description': 'This is the description shown in Google search results'
         }
       }
     })
     .when('/login', {
       templateUrl: 'login-template.html',
       data: {
         meta: {
           'title': 'Login page',
           'titleSuffix': ' | Login to YourSiteName',
           'description': 'Login to the site'
         }
       }
     });
     ...
   });

3. [Optional] Set the default values of meta tags during Angular's configuration phase. If the meta object of a route does not contain a specific tag, the default value is used instead.

   //Add a suffix to all page titles
   ngMetaProvider.useTitleSuffix(true);
    
   // On /home, the title would change to
   // 'Home Page | Best Website on the Internet!'
   ngMetaProvider.setDefaultTitleSuffix(' | Best Website on the Internet!');
    
   //Set defaults for arbitrary tags
   // Default author name
   ngMetaProvider.setDefaultTag('author', 'John Smith');

4. Let ngMeta initialize by calling the init() function in the app.js run block

   angular.module('YourApp', ['ngRoute', 'ngMeta'])
   .config(function($routeProvider, ngMetaProvider) {
     ....
   })
   .run(['ngMeta', function(ngMeta) {
     ngMeta.init();
   }]);

5. Set the meta tags in your HTML file

   <title ng-bind="ngMeta.title"></title>
    
   <!-- Arbitrary tags -->
   <meta property="og:type" content="{{ngMeta['og:type']}}" />
   <meta property="og:locale" content="{{ngMeta['og:locale']}}" />
   <meta name="author" content="{{ngMeta['author']}}" />
   <!-- OR <meta name="author" content="{{ngMeta.author}}" /> -->
   <meta name="description" content="{{ngMeta.description}}" />

Defaults

Change app-wide behaviour and set default values to tags using these methods of ngMetaProvider. These defaults can be overridden by defining equivalent properties in the route/state meta object

angular.module('YourApp', [....,'ngMeta'])
.config(function(ngMetaProvider) {
 
    ngMetaProvider.useTitleSuffix(true);
    ngMetaProvider.setDefaultTitle('Fallback Title');
    ngMetaProvider.setDefaultTitleSuffix(' | YourSite');
    ngMetaProvider.setDefaultTag('author', 'John Smith');
});

Method	Default	Example
useTitleSuffix(boolean) Toggles the use of a title suffix. When enabled, the title suffix of the route (if available) or the default title suffix is appended to the title of all pages.	false	ngMetaProvider.useTitleSuffix(true);
setDefaultTitle(String) Sets the default title for all routes. This serves as a fallback for routes that don't have a title property. Use this to customize titles for a few specific routes, letting other routes use the default title.	undefined	ngMetaProvider.setDefaultTitle('Spotify'); ngMetaProvider.setDefaultTitle('Generic Title');
setDefaultTitleSuffix(String) Sets the default title suffix for all routes. This serves as a fallback for routes that don't have a titleSuffix property. The default title suffix is relevant only when useTitleSuffix is set to true.	undefined	ngMetaProvider.setDefaultTitleSuffix(' - Site Name'); ngMetaProvider.setDefaultTitleSuffix(' - YourSite');
setDefaultTag(String, String) Sets the default value of any arbitrary tag. This serves as a fallback for routes that don't have a particular tag.	N/A	ngMetaProvider.setDefaultTag('author', 'John Smith'); ngMetaProvider.setDefaultTag('ogImgUrl', 'http://example.com/img.png');

Dynamic meta tags

To change meta tags dynamically (when an item in a list is clicked, for example), inject the ngMeta service into your controller and use one of the following methods:

angular.module('YourApp')
.controller(function(ngMeta) {
  //These examples assume useTitleSuffix is enabled,
  //and default titleSuffix is set to 'Playlist'
 
  //Custom title and titleSuffix
  ngMeta.setTitle('Eluvium', ' | Spotify'); //Title = Eluvium | Spotify
  //default titleSuffix
  ngMeta.setTitle('Eluvium'); //Title = Eluvium | Playlist
  //Clear the default titleSuffix
  ngMeta.setTitle('Eluvium',''); //Title = Eluvium
 
  ngMeta.setTag('author', 'Matthew Cooper');
  ngMeta.setTag('image', 'http://placeholder.com/abc.jpg');
 
  ngMeta.setDefaultTag('author', 'Default author');
  //Set default tags (non-default tags, like author and image above, are NOT cleared)
  ngMeta.resetMeta();
});

Note: Please use setTitle to modify the title and/or titleSuffix and setTag for all other tags.

Method	Description	Example
setTitle(String title, String titleSuffix)	Sets the current title based on the given params. When useTitleSuffix is enabled and titleSuffix is not provided, it uses the default titleSuffix.	ngMeta.setTitle('Title', ' - TitleSuffix') ngMeta.setTitle('Title with default titleSuffix') ngMeta.setTitle('Title with no titleSuffix','')
setTag(String tagName, String value)	Sets the value of an arbitrary tag, using the default value of the tag when the second param is missing. The value is accessible as {{ngMeta.tagName}} from HTML. Calling setTag with title or titleSuffix as tagName results in an error. Title must be modified using setTitle instead.	ngMeta.setTag('author', 'John Smith') ngMeta.setTag('ogImage', 'http://url.com/image.png')
setDefaultTag(String tagName, String value)	Sets the default value of an arbitrary tag, overwriting previously set default values, but not the value set dynamically (using setTitle/setTag) or by the route/state. title and titleSuffix are accepted values.	ngMeta.setDefaultTag('image', 'http://default-image-url.com'); ngMeta.setDefaultTag('title','Default title');
resetMeta(void)	Applies the default meta tags. This is relevant when using ui-router and disableUpdate: true (Refer this comment). Custom tags set dynamically (using setTag or setTitle) are not cleared.	ngMeta.resetMeta();

Debugging

• ng-inspector Chrome extension shows the tags set by ngMeta when a state/route is open

• Facebook's Open Graph Object Debugger shows detailed information about your site's meta tags as well as a preview of the snippet shown when your site is shared. Note that you need to use server-side rendering or prerendering in combination with ngMeta to see your meta tags in the the debugger

Advanced

Data inheritance in ui-router

If you wish to take advantage of nested views and data inheritence, then you should specify your meta config underneath the data property like this:

$stateProvider
  .state('services', {
    abstract: true,
    url: '/services',
    templateUrl: '/services/base.html',
    controller: 'servicesCtrl',
    data: {
      'meta': {
        'og:image': 'http://www.yourdomain.com/img/facebookimage.jpg',
        'author': 'PawSquad'
      }
    }
  })
  .state('services.vaccinations', {
    url: '/vaccinations',
    templateUrl: '/services/vaccinations.html',
    controller: '',
    data: {
      'meta': {
        'title': 'Pet Vaccinations - All You Need To Know | PawSquad',
        'og:title': 'All You Need To Know About Pet Vaccinations',
        'og:description': 'Useful information about Routine Vaccines and Boosters for dogs and cats,   including start vaccines for puppies and kittens.',
      }
    }
  })

Furthermore, you should use the helper function to decorate $stateProvider's data function like this

.config(['ngMetaProvider', function (ngMetaProvider) {
  $stateProvider.decorator('data', ngMetaProvider.mergeNestedStateData);
}])

In this way the metadata for the /services/vaccinations URL would be

  'meta': {
    'og:image': 'http://www.yourdomain.com/img/facebookimage.jpg',
    'author': 'PawSquad',
    'title': 'Pet Vaccinations - All You Need To Know | PawSquad',
    'og:title': 'All You Need To Know About Pet Vaccinations',
    'og:description': 'Useful information about Routine Vaccines and Boosters for dogs and cats, including start vaccines for puppies and kittens.'
  }

Using custom data resolved by ui-router

If you want to dynamically set your tags using ui-router's resolve, this is possible as well:

resolve: {
  data: function(..., ngMeta) {
    //Ex: Load data from HTTP endpoint
    ....
    ngMeta.setTitle();
    ngMeta.setTag('description', '....');
    ngMeta.setTag('image', '....');
  }
},
meta: {
  disableUpdate: true
}

The property disableUpdate: true is required because ui-router will execute the resolve function before the $stateChangeSuccess event is fired. Setting disableUpdate: true will prevent your tags from getting reset by the $stateChangeSuccess event listener.

Support for other crawlers

While Google is capable of rendering Angular sites, other search engines (?) and crawler bots used by social media platforms do not execute Javascript. This affects the site snippets generated by sites like Facebook and Twitter. They may show a snippet like this one:

You can use prerendering services to avoid this issue altogether, or update the server config to generate and serve a simplified page with just the open graph meta data needed for the bots to create snippets. Michael Bromley's article, Enable Rich Sharing In Your AngularJS App has more information on how to do that.

TL;DR: ngMeta helps the Google crawler render your Angular site and read the meta tags. For other sites like Facebook/Twitter that can't render Javascript, you need to use pre-renderers or server redirects.

Websites using ngMeta

• acloud.guru - AWS certification online learning platform

To list your website here, please make a PR (or edit README.md on GitHub) and add your URL in this section of README.md in this format

"Site URL - Short description"

Further reading

• AngularJS & SEO - finally a piece of cake
• Fetch as Google - Google Webmaster Tools
• Deprecating our AJAX crawling scheme - Google Webmaster Blog
• Open Graph protocol

MIT Licence

Vinay Gopinath