AngularJS中$q 服务的用法详解

var deferred = $q.defer();

function asyncTask() {
  var deferred = $q.defer();
  setTimeout(function () {
    if (Math.random() > 0.5) {
      deferred.resolve('成功结果');
    } else {
      deferred.reject('失败原因');
    }
  }, 1000);
  return deferred.promise;
}

asyncTask().then(
  function (result) {
    console.log(result);
  },
  function (error) {
    console.error(error);
  }
);

promise.then(onFulfilled, onRejected, onNotified);

promise
  .then(function (data) {
    return data + 1;
  })
  .then(function (data) {
    return data * 2;
  })
  .then(function (finalResult) {
    console.log(finalResult);
  });

promise.catch(function (reason) {
  // 错误处理
});

promise.then(null, function (reason) {});

asyncTask()
  .then(processData)
  .then(saveData)
  .catch(handleError);

asyncTask()
  .then(successHandler)
  .catch(errorHandler)
  .finally(function () {
    console.log('操作结束');
  });

$q.when(10).then(function (value) {
  console.log(value); // 10
});

return $q.reject('参数非法');

$q.all({
  user: getUser(),
  order: getOrder()
}).then(function (results) {
  console.log(results.user);
  console.log(results.order);
});

$q.when(data).then(function () {
  $scope.value = 123;
});

Promise.resolve().then(function () {
  $scope.value = 123;
  // 视图可能不会更新
});

app.service('UserService', function ($q, $http) {
  this.getUser = function (id) {
    var deferred = $q.defer();
    $http.get('/user/' + id)
      .then(function (res) {
        deferred.resolve(res.data);
      })
      .catch(function (err) {
        deferred.reject(err);
      });
    return deferred.promise;
  };
});

login()
  .then(loadProfile)
  .then(loadPermissions)
  .then(initApp)
  .catch(handleError);

return deferred;

return deferred.promise;

return $http.get('/api');