read line module for node js
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Read a file line by line.


Important. In node 10 there is a core module named readline. Please use linebyline instead, it is the same module just renamed:

Npm linebyline

npm install linebyline


npm install .
npm test

What's this?

Simple streaming readline module for NodeJS. Reads a file and buffers new lines emitting a line event for each line.



  var readline = require('linebyline'),
      rl = readline('./somefile.txt');
  rl.on('line', function(line, lineCount, byteCount) {
    // do something with the line of text
  .on('error', function(e) {
    // something went wrong

ASCII file decoding

As the underlying fs.createReadStream doesn't care about the specific ASCII encoding of the file, an alternative way to decode the file is by telling the readline library to retain buffer and then decoding it using a converter (e.g. iconv-lite).

  var readline = require('linebyline'),
      rl = readline('./file-in-win1251.txt', {
    retainBuffer: true //tell readline to retain buffer 
  rl.on("line", function (data,linecount){
    var line = iconv.decode(data, 'win1251');
    // do something with the line of converted text


readLine(readingObject[, options])


  • readingObject - file path or stream object
  • options can include:
    • maxLineLength - override the default 4K buffer size (lines longer than this will not be read)
    • retainBuffer - avoid converting to String prior to emitting 'line' event; will pass raw buffer with encoded data to the callback


  • EventEmitter


BSD © Craig Brookes