node.js - 无法访问 nodejs 代码中的值

Question

我的 nodejs 函数中有以下代码。即使 IF 条件为真，我也没有更新 stringResponse 变量的值。

var fs = require('fs'), 
                byline = require('byline');
            var stream = fs.createReadStream('Solutionbank.csv');
            var stringResponse = "We found a similar issue.  ";
            stream = byline.createStream(stream);
            stream.on('data', function(line) {
              var csvLine = line.toString('utf8');
                  csvLine = csvLine.toLowerCase().trim();

              var msgText = subject.toLowerCase().trim();
              //console.log("email block",msgText);
              if(csvLine.indexOf(msgText) > -1) {
                var arr = line.toString('utf8').split(",");

                stringResponse = stringResponse + "Issue ID"+arr[0]+",Subject : "+arr[1]+", Resolution Comment:"+arr[2];
                console.log(stringResponse);

                }
            });

            console.log("stringResponse from email",stringResponse);

Answer 1

线 ：

console.log("来自电子邮件的字符串响应",stringResponse);

是场外 on('data') 回调函数，在设置 stringResponse 变量之前调用此行。将其放在回调函数的末尾（内部）。或者在流结束时调用的另一个回调函数中：

stream.on('data', function(line) {
  ...
  console.log("stringResponse from email",stringResponse); // show each append 
});

  stream.on('end', function() {
  ...
  console.log("stringResponse from email",stringResponse); // show each append 
});