angularjs – 链接多个承诺,包括Promise.all

我已经有了需要在数组中压缩的文件列表.所以,我正在迭代它们并使用$cordovaFile获取这些文件的binay内容.然后我将二进制文件添加到JSZip对象.最终结果应该是将所有文件的二进制内容添加到zip.file中,以便生成zip文件.

//wrapping in Promise.all so that we don't proceed until we have the content of all files added to zip
var zip = new JSZip();
return Promise.all(
        filesList.forEach(function(file) {
           console.log('file to be added using $cordovaFile '+file); 
           // Getting the content of each file using $cordovaFile. This returns a promise. 
                  return $cordovaFile.readAsBinaryString(cordova.file.dataDirectory + $rootScope.username,file)
                       .then(function(binaryData) {
                        return new Promise(function(resolve,reject) {
                         //Adding content of all files to zip.file so that it can be zipped in the next step.
                            resolve(zip.file(file,binaryData,{binary: true}));
                        })        
                      })
                      .catch(function(error) {
                        console.log('Error during fetch content or zipping '+JSON.stringify(error));
                      })
                 })
             )

一旦zip.file拥有所有内容,我在JSZip中调用另一个生成zip的函数.这也会返回一个承诺,所以我需要链接到$cordovaFile.writeFile,以便zip可以在本地编写. $cordovaFile.writeFile还返回一个Promise,这将是链中的最后一个承诺.

.then(function(zipData) {
// async request to generate the zip
                return zipData.generateAsync({type:"blob"});
            }).then(function (blob) {
  // once we have the zip,save it to the device 
                $cordovaFile.writeFile(cordova.file.dataDirectory+$rootScope.username,'abc.zip',blob,true)
                .then(function(data) {
                   console.log('Zip file written to device at '+cordova.file.dataDirectory+$rootScope.username); 
                })
            }).catch(function(error) {
                console.log('Error while zipping and writing '+JSON.stringify(error));
            })

这就是完整代码的样子

var zipFiles = function(filesList) {
var zip = new JSZip();

             return Promise.all(
                filesList.forEach(function(file) {
                   return $cordovaFile.readAsBinaryString(cordova.file.dataDirectory + $rootScope.username,file)
                      .then(function(binaryData) {
                        return new Promise(function(resolve,reject) {
                            resolve(zip.file(file,{binary: true}));
                        })        
                      })
                      .catch(function(error) {
                        console.log('Error during fetch content or zipping '+JSON.stringify(error));
                      })
                 })
             )
            .then(function(zipData) {
                return zipData.generateAsync({type:"blob"});
            }).then(function (blob) {
                $cordovaFile.writeFile(cordova.file.dataDirectory+$rootScope.username,true)
                .then(function(data) {
                   console.log('Zip file written to device at '+cordova.file.dataDirectory+$rootScope.username); 
                })
            }).catch(function(error) {
                console.log('Error while zipping and writing '+JSON.stringify(error));
            }) 
}

挑战是在Promise.all完成后,没有任何东西被执行.因此,没有任何开始’然后(函数(zipData)’被执行.

我觉得这与我链接Promise的方式有关.任何帮助将受到高度赞赏.