angular.js - angualrjs, how to write the next step after the $http asynchronous operation is executed

Question

There are three steps
step1: $http.jsonp(url1)
step2: $http.jsonp(url2)
step3: assignment operation,
There is no order requirement for steps 1 and 2. 3 is required to be executed after steps 1 and 2 are completed;

Because steps 1 and 2 will be called in many places, we don’t want it to be

步骤1.success{
   步骤2.success{
      步骤3}} 这样的写法    

I hope to encapsulate steps 1 and 2 into a public method, and then execute step 3 sequentially. How should I write it in angularjs

Answer 1

Use events. Don’t use nesting

$scope.$on('step1success',function(){
    //步骤二代码
//执行完成后在回调函数中触发
    $scope.$emit('step2success');
});
$scope.$on('step2success',function(){
    //步骤3代码
//执行完成后在回调函数中触发
    $scope.$emit('step3success');
});
$scope.$on('step3success',function(){
    //全部执行完成
});

//步骤一代码
//执行完成后在回调函数中触发
$scope.$emit('step1success');

Answer 2

Use the $q service that comes with ng

let promises = {
    alpha: promiseAlpha(),
    beta: promiseBeta(),
    gamma: promiseGamma()
}
$q.all(promises).then((values) => {
    console.log(values.alpha); // value alpha
    console.log(values.beta); // value beta
    console.log(values.gamma); // value gamma

    complete();
});
// promises包含多个promise对象，当所有promise对象成功返回时，$q.all().then()中的成功方法才会被执行。

//  $http返回的正是promise对象

Answer 3

The author can learn about $q and promise objects. As shown above, Angular has $q.all(), which you can use.