Question

使用下面的代码，我正在读取.csv文件：

    var fileInput = document.getElementById("uploaded-file");
    var reader = new FileReader();
    reader.onload = function () {
        var students_data = reader.result.split(/\r?\n|\r/);
        for(var count = 1; count<students_data.length; count++){
               var str_students_information = students_data[count];
               var arr_students_information = str_students_information.split(',');
               var a_student_info = [
                   {name: 'student', value: 'add-student'},
                   {name:"id",value:arr_students_information[0]},
                   {name:"name",value:arr_students_information[1]},
                   {name:"mname",value:arr_students_information[2]},
                   {name:"sname",value:arr_students_information[3]}
               ];
              sendToDatabase(a_student_info);
        }
    };
    reader.readAsBinaryString(fileInput.files[0]);

我的目标是在读取文件时每2秒调用一次方法sendToDatabase()。换句话说，在读取文档的一行之后，调用该方法并等待2秒钟，然后再读取下一行。
在主题setTimeout in for-loop does not print consecutive values的帮助下，我正在玩setTimeout()，但始终没有我需要的东西……可能我错过了一些东西……

Answer 1

由于您要定期执行某项操作，因此应使用setInterval()。在循环函数中增加数组索引，而不是循环。

var fileInput = document.getElementById("uploaded-file");
var reader = new FileReader();
reader.onload = function() {
  var students_data = reader.result.split(/\r?\n|\r/);
  var count = 1;
  var interval = setInterval(function() {
    if (count >= students_data.length) {
      clearInterval(interval);
      return;
    }
    var str_students_information = students_data[count];
    var arr_students_information = str_students_information.split(',');
    var a_student_info = [{
       {name: 'student', value: 'add-student'},
       {name:"id",value:arr_students_information[0]},
       {name:"name",value:arr_students_information[1]},
       {name:"mname",value:arr_students_information[2]},
       {name:"sname",value:arr_students_information[3]}

    ];
    sendToDatabase(a_student_info);
    count++;
  }, 2000);
};
reader.readAsBinaryString(fileInput.files[0]);

Answer 2

我相信这可以工作：

for(....) {
 .
 .
 .
  (function(student_info) {
      sendToDatabase(student_info); 
  })(a_student_info);
}

读取文件时的setTimeout

2 个答案: