Question

我有两个功能，一个用于获取内容，另一个用于保存。内容不同，我需要执行不同的任务。我事先知道什么类型的内容，这两个只是助手功能。

我正在使用asyncfuncA（）。然后（asyncFuncB）.then（...）;但我认为我可以使用链接A和B的函数并像asyncfuncAB.then（...）一样使用它，但我遇到了问题。以下简化代码解释了我想做的事情。

     function getCont(url) {
        return new Promise(function (resolve ,reject) {
      // The real code makes request and resolves to response body or rejects with error
     resolve("response body");
        });
     }

     function saveFile  (path,data) {
       return new Promise(function (resolve ,reject) {
     // The real code writes file and resolves to true for success or rejects for error
     resolve(true);
        });
      }

     saveCont("some://url","/some/path").then ( function() {
      // Do some thing for one type of content 
     });

     saveCont("another://url","/another/path").then ( function() {
     // Do another thing for another type of content
     });


    function saveCont(url,path) {
         getCont(url)
         .then(function(content) {
         saveFile(path,data) })
        .then( function() {
         // **  What to put here ??

         });
     };

Answer 1

你最后不需要放任何东西，只需返回Promise对象：

function saveCont(url,path) {
     return getCont(url)     //CHANGED
     .then(function(content) {
        return saveFile(path,data);   // if you do not put a return here, saveFile would still work, but the next step in chain would not wait till SaveFile finishes processing. 
     });
 };

使用链接承诺的函数

1 个答案: