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Chaining promises in Javascript and Angular


I am using Angular resourse to get my data from an API, in this way:

var getAccountListPerUser = function () {

  return $resource(uri, {}, {
    get: {
      headers: service.getDefaultHeaderRequest(),
      method: 'GET',
      transformResponse: function (data) {
        var accountList = [];
        try {
          accountList = JSON.parse(data);
        } catch (e) {
          accountList = [];
        }
        return accountList;
      },
      isArray: true,
      cache: true
    }
  }).get().$promise;
};

In my controller I have to use it and another two service functions defined in the same way.

var promiseResourcesAccountList = usrWebUserService.getAccountListPerUser();

promiseResourcesAccountList.then(function(result){
  $scope.usersWithAccountsAndProfiles = result;
  var filteredProfiles = [];
  for (var account in result) {
    ...
  }
  $scope.filteredProfiles = filteredProfiles;
});

And:

var promiseResourcesEditUser = usrWebUserService.getResourcesUser(currentUser);

promiseResourcesEditUser.then(function (result) {
  usrWebUserFactory.mapBasicPreferences($scope, result);
});

And then another very similar, this information loads data in three divs, but I want to show them only when all the three functions have completed correctly. I think I have to chain the result of the promises. How can I do that?


Solution

  • You can chain them like:

    promiseResourcesAccountList.then(function(result){
      ///whatever processing
      //return a promise
      return promiseResourcesEditUser()
    }).then(function(){
      return anotherPromise();
    }).then(function(){
       //update scope here
    });
    

    alternatively, you could also use $q.all([promise1, promise2, promise3]).then(...);