Question

我有一个应该返回promise的AngularJS服务方法。在该方法中是异步调用，在成功时继续执行$ http调用。我的语法不正确，无法正确返回。

// This function should return a promise
function doFacebook() {

  var deferred = $q.defer();

  Facebook.login(function(response) {

    var p = $http({
      method: 'POST',
      url: '/auth/facebook',
      data: {
        token: response.authResponse.accessToken
      }
    });
    p.then(function(data) {
      startSession(data);
      return data;
    }, function(data) {
      return $q.reject(data);
    });
  });

  return deferred.promise;
}

我想要返回p - 不确定如何附加/替换延迟p。

Answer 1

您可以使用facebook登录回调中的http调用返回的promise p来解析延迟对象。它应该自动解决/拒绝传入的承诺。

function doFacebook() {
  var deferred = $q.defer();
  Facebook.login(function(response) {
    var p = $http({
      method: 'POST',
      url: '/auth/facebook',
      data: {
        token: response.authResponse.accessToken
      }
    }).then(function(data) {
      startSession(data);
      return data;
    }, function(data) {
      return $q.reject(data);
    });
    //Here
    deferred.resolve(p);
  });

  return deferred.promise;
}

示例演示： -

///BAD CODE ALERT!!

angular.module('app', []).controller('ctrl', function($scope, $q, $http, $timeout) {

  function doAsync() {

    var deferred = $q.defer();

    //Simulating non angular async
    setTimeout(function() {
      //Simulating http call. $timeout also returns a promise, so.
      var p = $timeout(function() {
        //uncomment to test reject scenario
        if ($scope.reject) {
          $scope.reject = false;
          throw Error("OOPS i got rejected");
        }
        return 'Hello, i got resolved!!'
      }).then(function(data) {
        return data;
      }, function(data) {
        return $q.reject(data.message);
      });
      //Here
      deferred.resolve(p);
    });

    return deferred.promise;
  }
  $scope.runTest = function() {
    doAsync().then(function(data) {
      $scope.data = data;
    }).catch(function(error) {
      $scope.data = error;
    });
  }
  $scope.rejectTest = function() {
    $scope.reject = true;
  }

})

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="app" ng-controller="ctrl">
  
  <button ng-click="rejectTest()">Reject and then</button>
  <button ng-click="runTest()">Run Test</button>
  <div>{{data}}</div>
</div>

在异步函数中返回promise

1 个答案: