#eachline

Streams2 line reader / stream transformer.

First let me say: I did NOT want to write yet another line reader! I couldn't find one that is working with node's new Streams2 objects.

The byline module has taken a first stab at it, but it isn't working. (as of 32bf791e38)

So here we are...

var fs = require('fs');
var eachline = require('eachline');
var stream = fs.createReadStream(__dirname+'/.gitignore');

eachline(stream, function(line){
  console.log(line);
});

However, if you're just looking to open a file:

var eachline = require('eachline');
eachline.in(__dirname+'/.gitignore', function(line){
  console.log(line);
});

...or if you need a simple http GET:

var eachline = require('eachline');
var url = 'https://raw.github.com/williamkapke/node-eachline/master/.gitignore';
eachline.in(url, function(line){
  console.log(line);
});

##Transforming Streams eachline uses Streams2's transformation feature allowing you to throw eachline between .pipe()s to modify output as needed.

var fs = require('fs');
var eachline = require('eachline');
var file = fs.createReadStream(__dirname+'/.gitignore');

var transformer = eachline(function(data){
  return data.substr(0, 2)+'\n';
});

file.pipe(transformer).pipe(process.stdout);

##API ###eachline() Use with a pipe() to re-chunk the stream into lines.

###eachline([encoding,] callback) Use with pipe() optionally specifying the encoding.

###eachline(ReadableStream,[ encoding,] callback) Got that stream ready? Pass it in, get them lines. Easy-peasy.

###eachline.in(url, callback) eachline.in(filepath, callback) Just a helper function to make these simple tasks cleaner.

It returns the Transform stream so you can listen to the events.

var linecount = 0;
var eachline = require('eachline');
eachline.in(__dirname+'/.gitignore', function(data){
	linecount++;
})
.on('finish', function(){
	console.log(linecount + " lines found");
});

##callback(data, lineno[ ,next]) The callback arguments above will be called for every line found in the ReadableStream.

It will be passed the data and lineno arguments. You can optionally defined a 3rd argument to get asynchronous flow. eachline examines callback.length to detirmine if asynchronous flow should be used. If found, you must call next() to continue reading.

For Stream transformations, any value return'd will be written to the next pipe() in the chain.

###this.finished Inside the callback function, this refers to the transformer. For convenience of detecting the final line of the stream, there is a this.finished property.

var fs = require("fs");
var eachline = require("eachline");

fs.createReadStream('./.gitignore')
  .pipe(eachline(function(line, i){
    //only write the last line if it is not empty
    if(!this.finished || line)
      console.log(i, line);
  }));

License

The MIT License (MIT)

Copyright (c) 2013 William Kapke

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.