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readline

readline

Read a file line by line.

Install

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

Test

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.

Usage

Simple

  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 
  });

API

readLine(readingObject[, options])

Params:

  • 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

Return:

  • EventEmitter

License

BSD © Craig Brookes