How can I add some small utility functions to my AngularJS application

Question

I would like to add some utility functions to my AngularJS application  For example    scope isNotString   function  str        return  typeof str      string        Is the best way to do this to add them as a service  From what I have read I can do  this but then I would like to use these in my HTML pages so is it still possible if they are in a service  For example can I use the following     lt button data-ng-click  doSomething             data-ng-disabled  isNotString abc   gt Do Something   lt  button gt    Can someone give me an example of how I could add these  Should I create a service or is there some other way of doing it  Most important I would like these utility functions in a file and not combined with another part of the main set up   I understand there s a few solutions but none of them are so clear   Solution 1 - Proposed by Urban   scope doSomething   ServiceName functionName    The problem here is I have 20 functions and ten controllers  If I did this it would mean adding a lot of code to each controller   Solution 2 - Proposed by me      var factory              Setup  function   scope                  scope isNotString   function  str                    return  typeof str      string                    The disadvantage of this is that at the start of every controller I would have one or more of these Setup calls to each service which passed the  scope   Solution 3 - Proposed by Urban  The solution proposed by urban of creating a generic service looks good  Here s my main set up   var app   angular      module  app     ngAnimate    ui router    admin    home    questions    ngResource    LocalStorageModule         config    locationProvider     sceProvider     stateProvider           function   locationProvider   sceProvider   stateProvider                  sceProvider enabled false                locationProvider html5Mode true     Should I add the generic service to this and how could I do it

User · Answer

Here is a simple  compact and easy to understand method I use  First  add a service in your js   app factory  Helpers     function              Helper service body          var o             Helpers                             Dummy function with parameter being passed         o getFooBar   function para                 var valueIneed   para          World                 return valueIneed                            Other helper functions can be added here                 And we return the helper object             return o              Then  in your controller  inject your helper object and use any available function with something like the following   app controller  MainCtrl        scope    Helpers    function  scope  Helpers         scope sayIt   Helpers getFooBar  Hello        console log  scope sayIt

User · Answer

Do I understand correctly that you just want to define some utility methods and make them available in templates   You don t have to add them to every controller   Just define a single controller for all the utility methods and attach that controller to  lt html  or  lt body   using the ngController directive    Any other controllers you attach anywhere under  lt html   meaning anywhere  period  or  lt body   anywhere but  lt head   will inherit that  scope and will have access to those methods

User · Answer

The easiest way to add utility functions is to leave them at the global level   function myUtilityFunction x    return  do something with   x      Then  the simplest way to add a utility function  to a controller  is to assign it to  scope  like this    scope doSomething   myUtilityFunction    Then you can call it like this      doSomething x       or like this   ng-click  doSomething x     EDIT   The original question is if the best way to add a utility function is through a service   I say no  if the function is simple enough  like the isNotString   example provided by the OP    The benefit of writing a service is to replace it with another  via injection  for the purpose of testing   Taken to an extreme  do you need to inject every single utility function into your controller   The documentation says to simply define behavior in the controller  like  scope double   http   docs angularjs org guide controller

User · Answer

Why not use controller inheritance  all methods properties defined in scope of HeaderCtrl are accessible in the controller inside ng-view   scope servHelper is accessible in all your controllers       angular module  fnetApp   controller  HeaderCtrl   function   scope  MyHelperService           scope servHelper   MyHelperService             lt div ng-controller  HeaderCtrl  gt     lt div ng-view    gt  lt  div gt   lt  div gt

User · Answer

You can also use the constant service as such   Defining the function outside of the constant call allows it to be recursive as well    function doSomething  a  b         return a   b      angular module  moduleName             Define      constant   doSomething   doSomething         Usage      controller   SomeController   function   doSomething              scope added    doSomething  100  200

User · Answer

EDIT 7 1 15    I wrote this answer a pretty long time ago and haven t been keeping up a lot with angular for a while  but it seems as though this answer is still relatively popular  so I wanted to point out that a couple of the point  nicolas makes below are good  For one  injecting  rootScope and attaching the helpers there will keep you from having to add them for every controller  Also - I agree that if what you re adding should be thought of as Angular services OR filters  they should be adopted into the code in that manner    Also  as of the current version 1 4 2  Angular exposes a  Provider  API  which is allowed to be injected into config blocks  See these resources for more   https   docs angularjs org guide module module-loading-dependencies  AngularJS dependency injection of value inside of module config  I don t think I m going to update the actual code blocks below  because I m not really actively using Angular these days and I don t really want to hazard a new answer without feeling comfortable that it s actually conforming to new best practices  If someone else feels up to it  by all means go for it    EDIT 2 3 14   After thinking about this and reading some of the other answers  I actually think I prefer a variation of the method brought up by  Brent Washburne and  Amogh Talpallikar  Especially if you re looking for utilities like isNotString   or similar  One of the clear advantages here is that you can re-use them outside of your angular code and you can use them inside of your config function  which you can t do with services    That being said  if you re looking for a generic way to re-use what should properly be services  the old answer I think is still a good one    What I would do now is   app js   var MyNamespace   MyNamespace          MyNamespace helpers        isNotString  function str         return  typeof str      string               angular module  app     app controllers    app services                                     config    routeProvider   function  routeProvider            Routing stuff here              controller js   angular module  app controllers                                                                                                                                                                                            controller  firstCtrl      scope   function  scope         scope helpers   MyNamespace helpers          Then in your partial you can use    lt button data-ng-click  console log helpers isNotString  this is a string     gt Log String Test lt  button gt    Old answer below   It might be best to include them as a service  If you re going to re-use them across multiple controllers  including them as a service will keep you from having to repeat code   If you d like to use the service functions in your html partial  then you should add them to that controller s scope    scope doSomething   ServiceName functionName   Then in your partial you can use    lt button data-ng-click  doSomething    gt Do Something lt  button gt    Here s a way you might keep this all organized and free from too much hassle   Separate your controller  service and routing code config into three files  controllers js  services js  and app js  The top layer module is  app   which has app controllers and app services as dependencies  Then app controllers and app services can be declared as modules in their own files  This organizational structure is just taken from Angular Seed   app js    angular module  app     app controllers    app services                                     config    routeProvider   function  routeProvider            Routing stuff here                services js       Generic Services                                                                                                                                                                                                         angular module  app services                                                                                                                                                                                   factory  genericServices   function                                                                                                                                                             return                                                                                                                                                                                                                        doSomething  function                   Do something here                  doSomethingElse  function                Do something else here                    controller js   angular module  app controllers                                                                                                                                                                                            controller  firstCtrl      scope    genericServices   function  scope  genericServices         scope genericServices   genericServices          Then in your partial you can use    lt button data-ng-click  genericServices doSomething    gt Do Something lt  button gt   lt button data-ng-click  genericServices doSomethingElse    gt Do Something Else lt  button gt    That way you only add one line of code to each controller and are able to access any of the services functions wherever that scope is accessible

User · Answer

Coming on this old thread i wanted to stress that   1    utility functions may  should   be added to the rootscope via module run  There is no need to instanciate a specific root level controller for this purpose   angular module  myApp   run function  rootScope      rootScope isNotString   function str       return  typeof str      string              2    If you organize your code into separate modules you should use angular services or factory and then inject them into the function passed to the run block  as follow    angular module  myApp   factory  myHelperMethods   function      return       isNotString  function str          return  typeof str      string                   angular module  myApp   run function  rootScope  myHelperMethods       rootScope helpers   myHelperMethods        3    My understanding is that in views  for most of the cases you need these helper functions to apply some kind of formatting to strings you display  What you need in this last case is to use angular filters  And if you have structured some low level helper methods into angular services or factory  just inject them within your filter constructor    angular module  myApp   filter  myFilter   function myHelperMethods      return function aString       if  myHelperMethods isNotString aString          return            else           something else                 And in your view        aString   myFilter

[angularjs] How can I add some small utility functions to my AngularJS application?

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