Question

我有一组getJson（）函数，我使用jquery deferred连续调用。

function f1(){ $.getJSON(..)}
function f2(){ $.getJSON(..)}
....
function fn(){ $.getJSON(..)}

var dfd = $.Deferred();
dfd.done(f1,f2...fn)

dfd.resolve();

问题是，其中一个函数可能遇到一个给定的问题并返回 False ，在这种情况下我想停止进度而不是调用剩余的函数。

我该怎么做？

Answer 1

你可以这两种方式

<强> 1。如果回答不相互依赖

var req1 = $.getJSON(...).then(function(response1) {
     //evaluate the response and either reject or resolve a Deferred based on the results of your evaluation
     if(!response1) { return $.Deferred().reject(); }
     return $.Deferred().resolve(response1);
});

var req2 = $.getJSON(...).then(function(response2) {
     //evaluate the response
     if(!response1) { return $.Deferred().reject(); }
     return $.Deferred().resolve(response2);
});

var req3 = $.getJSON(...).then(function(response3) {
     //evaluate the response
     if(!response1) { return $.Deferred().reject(); }
     return $.Deferred().resolve(response3);
});

var req4 = $.getJSON(...).then(function(response4) {
     //evaluate the response
     if(!response1) { return $.Deferred().reject(); }
     return $.Deferred().resolve(response4);
});

$.when(req1,req2,req3,req4)
  .then(
    function(response1,response2,response3,response4) { /* called when all requests are successfully complete */ },
    function() { /* called when any of the requests have failed */ }
   );

<强> 2。如果答案相互依赖

$.getJSON(...) //req1

 .then(function(response1) {

    //evaluate response1
   if(!response1) { return $.Deferred().reject(); }
   return $.Deferred().resolve(response1);

 })
 .then(function(response1) {

   return $.getJSON(...).then(function(response2) {
     //evaluate the response
     if(!response2) { return $.Deferred().reject(); }
     return $.Deferred().resolve(response1,response2);
   });

 })
 .then(function(response1,response2) {

   return $.getJSON(...).then(function(response3) {
     //evaluate the response
     if(!response2) { return $.Deferred().reject(); }
     return $.Deferred().resolve(response1,response2,response3);
   });

 })
 .then(function(response1,response2,response3) {

   return $.getJSON(...).then(function(response4) {
     //evaluate the response
     if(!response4) { return $.Deferred().reject(); }
     return $.Deferred().resolve(response1,response2,response3,response4);
   });

 })
 .then(

   function(response1,response2,response3,response4) {
     //only called on success of all requests
  },

  function() {
    //called on failure of any individual request, or if the responses of any individual request did not meet your conditions
  }
)

修改

如果您在函数中执行这些操作，那么您只需返回承诺并将其链接到.then，如下所示：

function makeReqs() { //method 1 return $.when(req1,req2,req3,req4); //method 2 return $.getJSON(...) .then(...) .then(...) .then(...) } //call the function makeReqs .then( function() { /* this is called on success */ }, function() { /* this is called on failure */ } )

jQuery延迟：当条件未经验证时停止进度

1 个答案: