javascript - 如何在 angularJS 中观看 promise ？

Question

目标:$scope.finalArray = $scope.arrayFromPromise2.concat($scope.arrayFromPromise1);

第一种方法

 $scope.arrayFromPromise1 = [];
 $scope.arrayFromPromise2 = [];

 someService.query1()
   .then(function(success){
      $scope.arrayFromPromise1 = success.data;
      return someService.query2();
   })
   .then(function(success){
      $scope.arrayFromPromise2 = success.data;
      $scope.finalArray =  $scope.arrayFromPromise2.concat($scope.arrayFromPromise1);
   });

第二种方法

$scope.arrayFromPromise1 = [];
$scope.arrayFromPromise2 = [];

function getData1(){
  someService.query1().then(function(success){
    $scope.arrayFromPromise1 = success.data
  });
}

function getData2(){
  someService.query2().then(function(success){
   $scope.arrayFromPromise2 = success.data;

   $scope.finalArray =  $scope.arrayFromPromise2.concat($scope.arrayFromPromise1);
  });
}

getData1();
getData2();

第二种方法 将根据 getData1 的第一个 promise 完成的时间抛出错误。 可以在 getData2 中使用 $scope.$watch 以便我可以观察 $scope.arrayFromPromise1 的变化吗？任何与链接 promise 不同的提示？

Answer 1

使用 $q.all 等待一堆 promise 完成然后根据信息采取行动是一项简单的任务。方法。

//We are returned a promise with a .then block to extract the data
//this is making a certain assumption that we are using the $http service
//where as using another such as $resource or restangular will "unwrap"
//the data for us...

var query1Promise = someService.query1().then(function(res) { return res.data; });
var query2Promise = someService.query2().then(function(res) { return res.data; });

$q.all([query1Promise, query2Promise])
    .then(function(promises) {
         $scope.finalArray = promises[0].concat(promises[1]);
    });