数组循环中的AJAX调用，仅在上一个完成后才调用下一个 [英] AJAX call in array loop, call next only after previous complete

问题描述

我有一个数组来上传数据，并且我希望它们被一一发送到服务器. 我要先完成上一个，然后再发送下一个. 实际上，在每个响应之后，我都想决定是否发送下一个.

I have an array to upload data and I want them to send to server one by one. I want the previous one to complete before I send next one. Actually, after each response I want to decide whether to send next one or not.

while (packetCount < bulkUploadPackets.length) {
  d = d.then(save(bulkUploadPackets[packetCount]))
    .then(function(uploadResponse) {
      //I want to come here after first call complete 
      //before second call is fired and so on
      packetCount++;
    });
}


save: function(modelToSave) {
  var defer = $.Deferred();
  var self = this;
  this.model = modelToSave;
  Backbone.sync('create', this, {
    success: function(data, textStatus, jqXHR) {
      console.log("success" + data);
      defer.resolve(data);
    },
    error: function(response) {
      defer.reject(errorObj);
    }
  });

  return defer.promise();
}

推荐答案

您可以使用递归函数，然后将递归调用放在其中:

You can use recursive function and put recursive call inside then:

(function loop() {
     if (packetCount<bulkUploadPackets.length) {
           d = d.then(save(bulkUploadPackets[packetCount]))
                .then(function(uploadResponse){
                      //I want to come here after first call complete before second call is fired and so on
                      packetCount++;
                      loop();
                 }); 
     }
})();

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