根据node.js中的行数拆分文本文件

Question

在这里达到我的理解极限。 我有一个大的文本文件，我需要将其分成200行（使用mime.types进行练习）。 我正在使用readline但似乎忽略了我的pause / resume语句。 我想念什么：

// Splits a given file into smaller subfiles by line number
var infileName = 'mime.types';
var fileCount = 1;
var count = 0;
var fs = require('fs');
var outfileName = infileName + '.' + fileCount;
var inStream = fs.createReadStream(infileName);
var outStream = fs.createWriteStream(outfileName);
var lineReader = require('readline').createInterface({
  input: inStream
});

lineReader.on('line', function(line) {
  count++;
  lineReader.pause();
  outStream.write(line + '\n');
  if (count >= 200) {
    fileCount++;
    console.log('file ', outfileName, count);
    outStream.close();
    outfileName = infileName + '.' + fileCount;
    outStream = fs.createWriteStream(outfileName);
    count = 0;
  }
  lineReader.resume();
});

lineReader.on('close', function() {
  if (count > 0) {
    console.log('Final close:', outfileName, count);
  }
  inStream.close();
  outStream.close();
  console.log('Done');
});

我还尝试将流的更改放入写操作的回调中：

lineReader.on('line', function(line) {
  count++;
  lineReader.pause();
  outStream.write(line + '\n', function() {
    if (count >= 200) {
      fileCount++;
      console.log('file ', outfileName, count);
      outStream.close();
      outfileName = infileName + '.' + fileCount;
      outStream = fs.createWriteStream(outfileName);
      count = 0;
    }
    lineReader.resume();
  });
});

在两种情况下，结果是相同的：
node split file mime.types.1 1588 Done

理想情况下，我想要一个不依赖额外npm的解决方案

Answer 1

我摆脱了暂停/恢复。 它们似乎不受readline流的支持。 我所做的就是每200行提供一个新的可写流。

 // Splits a given file into smaller subfiles by line number var infileName = 'mime.types'; var fileCount = 1; var count = 0; var fs = require('fs'); var outStream; var outfileName = infileName + '.' + fileCount; newWriteStream(); var inStream = fs.createReadStream(infileName); var lineReader = require('readline').createInterface({ input: inStream }); function newWriteStream(){ outfileName = infileName + '.' + fileCount; outStream = fs.createWriteStream(outfileName); count = 0; } lineReader.on('line', function(line) { count++; outStream.write(line + '\\n'); if (count >= 200) { fileCount++; console.log('file ', outfileName, count); outStream.end(); newWriteStream(); } }); lineReader.on('close', function() { if (count > 0) { console.log('Final close:', outfileName, count); } inStream.close(); outStream.end(); console.log('Done'); });