Angular.foreach 异步回调不起作用

Question

我正在尝试检测 foreach 语句是否与 foreach 中的语句一起完成。根据我的研究，许多人要求使用 Promise。当我实现它时，它并没有按照我期望的方式执行。

var uploadUrl = "/api/upload";
$('#add_product').closeModal();
 var promises = angular.forEach(vm.images_selected, function(value , key){
    return File_Upload.uploadFileToUrl(value, uploadUrl)
    .success(function(result){
        vm.images_selected_uploaded.push(result);
        console.log('here')
    });
})
$q.all(promises).then(function () {
    console.log('there')
    console.log(vm.images_selected_uploaded)
})

从上面的代码（假设值长度为2，输出将是

there
here
here

我真正想要的是这里这里那里。我在这里错过了什么？

Answer 1

第一个问题，angular.forEach 返回对第一个参数的引用，因此它们不会是您正在寻找的承诺

第二个问题，angular 并没有替代 .map

如果你将 promise 保存在 promises 数组中，你可以这样做

var uploadUrl = "/api/upload";
$('#add_product').closeModal();
var promises = [];
angular.forEach(vm.images_selected, function(value , key){
    promises.push(File_Upload.uploadFileToUrl(value, uploadUrl)
        .success(function(result){
            vm.images_selected_uploaded.push(result);
            console.log('here')
        })
    );
})
$q.all(promises).then(function () {
    console.log('there')
    console.log(vm.images_selected_uploaded)
});

Answer 2

类似这样的：

var uploadUrl = "/api/upload";
$('#add_product').closeModal();
var promises = [];
angular.forEach(vm.images_selected, function(value , key){
    promises.push(File_Upload.uploadFileToUrl(value, uploadUrl));
});
$q.all(promises).then(function (results) {
    for(var i = 0; i < results.length; i++){
       var result = results[i];
       vm.images_selected_uploaded.push(result);
       console.log('here');
    }
    console.log('there');
    console.log(vm.images_selected_uploaded);
})

或者可能是这样的：

var uploadUrl = "/api/upload";
$('#add_product').closeModal();
 var promises = [];
 angular.forEach(vm.images_selected, function(value , key){
    var promise = File_Upload.uploadFileToUrl(value, uploadUrl);
    promise.success(function(result){
        vm.images_selected_uploaded.push(result);
        console.log('here');
    });
    promises.push(promise);
})
$q.all(promises).then(function () {
    console.log('there');
    console.log(vm.images_selected_uploaded);
})

顺便说一句，两者都未经测试。