Question

例如，我有四个功能：

var f1 = function() {...};
var f2 = function() {...};
var f3 = function() {...};
var f4 = function() {...};
var fmain = function() {...};

主要功能是for循环：

  var fmain = function () {
    angular.forEach(question_list, function (question, key) {

      f3();  //I want to execute f4() after f3() is returned!

      f4();

    });

  };

在f3()中，f2()被调用！

var f2() = function(){
//There's a timeout function to check if the dynamic value equals to the expected value
//if so, then return true; otherwise, keep calling f2() until the dynamic value equals to the expected value
}

在f2()中，f1()被调用！

var f1() = function(){
//There's a timeout function to check if the dynamic value equals to the expected value
//if so, then return true; otherwise, keep calling f1() until the dynamic value equals to the expected value
}

因此，f3取决于f2，f2取决于f1。

我想让它们同步返回（如果还没有返回上一行，则需要代码不要进入下一行）。我该如何实现呢？

提前致谢！

Answer 1

您可以使用$q服务：

var f1() = function(){
    var defer = $q.defer();
    $timeout(function(){
        defer.resolve(f1result);
    });
    return defer.promise;
}

var f2() = function(){
   var defer = $q.defer();
   f1().then(function(f1result){
         defer.resolve(f2result);
   });
   return defer.promise;
}

f3功能可以像f1和f2一样工作（推迟，保证和解决）。

var fmain = function () {
angular.forEach(question_list, function (question, key) {
  f3().then(function(f3result){
      f4();
  });
});
};

Answer 2

        return A()
            .then(function (response) {
                //this portion of code in then of A() (let's call it function B) will execute only after A() provides a response or is resolved.
                if (response.isAllowed == true) {
                    otherData = myFactory.getOtherDataFromServiceOne();
                }
                else {
                    otherData = hisFactory.getOtherDataFromServiceTwo();
                }
                return $q.all([
                    otherData
                ]).then(function (results) {
                    return {
                        otherData: results[0]
                    };
                });
            });
    }


    function A() {
            var isAllowed = myFactory.isAllowed(userId);
            return $q.all([
                isAllowed 
            ]).then(function (results) {
                return {
                    isAllowed : results[0].data;
                };
            });
    };

我在这里提到$ q.all仅用于表示我们可以在这里使用的每个$ q.all中传递尽可能多的函数，否则你可以简单地使用$ promise。

如何同步调用多个函数angularjs

2 个答案: