gen-readlines

A generator based line reader. This node package will return the lines of a file as a generator when given file descriptor and the size of the file.

Install

npm install gen-readlines

Usage

Provide readlines with a file descriptor and the size of the file and it will create a generator which will iterate through all the lines in that file.

var fs = require('fs');
var readlines = require('gen-readlines');

var fd = fs.openSync('./test_data/hipster.txt', 'r');
var stats = fs.fstatSync(fd);

for (let line of readlines(fd, stats.size)) {
  console.log(line.toString());
}

fs.closeSync(fd);

fs.open('./test_data/hipster.txt', 'r', function(err, fd) {
  if (err) throw err;
  fs.fstat(fd, function(err, stats) {
    if (err) throw err;

    for (let line of readlines(fd, stats.size)) {
      console.log(line.toString());
    }

  });
});

readlines returns a generator object and calling next will get the next line as a buffer object:

var file = readlines(fd, stats.size);
var line = file.next();
console.log(line);
> { value: <Buffer 42 65 73 70 ... >, done: false }

Convert the buffer to a string:

line.toString();
> This is the first line of the file

Compatibility

• node 0.11.x or greater, with --harmony-generators flag or --harmony to get access to generators.
• io.js is supported without any flags.

Documentation

readlines (fd, filesize, bufferSize=64*1024, position=0)

• fd {Number} The file descriptor
• filesize {Number} The size of the file in bytes
• bufferSize {Number} The size of the buffer in bytes, default: 64*1024
• position {Number} The position where to start reading the file in bytes, default: 0

Testing

We are using mocha for unit testing

npm test