stream-eachline

Like readline or split, but behaves more like ruby's .each_with_index method when streams lack trailing newlines.

Getting Started

Install the module with: npm install stream-eachline

var eachline = require('stream-eachline').eachline;

// Modify each line in process.stdin input stream (while streaming)
// and when done log an array of modified lines.
eachline(process.stdin, function(line, index) {
  return '[' + index + '] ' + line.toUpperCase();
}, function(lines) {
  console.log('Array of modified lines:', lines);
});

// The following examples all do the same thing:
eachline(process.stdin, function(line, index) {
  return line;
}, function(lines) {
  doSomethingWithLines(lines);
});

// You may omit lineFunction if you don't need to modify the streamed lines.
eachline(process.stdin, doSomethingWithLines);

// You may omit instream if you want to process process.stdin's lines.
eachline(doSomethingWithLines);

Documentation

eachline([instream], [lineFunction], doneFunction)

Why this library?

# I couldn't get readline to give me the last line of a stream if there
# was no trailing newline.
$ echo -en 'foo\nbar\nbaz\n' | node examples/readline-broken.js
[ '[0] <foo>', '[1] <bar>', '[2] <baz>' ]

$ echo -en 'foo\nbar\nbaz' | node examples/readline-broken.js
[ '[0] <foo>', '[1] <bar>' ]


# This is the behavior I expected, based on my experience with ruby's
# STDIN.each_with_index method.
$ echo -en 'foo\nbar\nbaz\n' | ruby examples/each-with-index.rb
["[0] <foo>", "[1] <bar>", "[2] <baz>"]

$ echo -en 'foo\nbar\nbaz' | ruby examples/each-with-index.rb
["[0] <foo>", "[1] <bar>", "[2] <baz>"]


# This lib behaves more like ruby's STDIN.each_with_index method.
$ echo -en 'foo\nbar\nbaz\n' | node examples/eachline-yay.js
[ '[0] <foo>', '[1] <bar>', '[2] <baz>' ]

$ echo -en 'foo\nbar\nbaz' | node examples/eachline-yay.js
[ '[0] <foo>', '[1] <bar>', '[2] <baz>' ]

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.

Release History

(Nothing yet)

License

Copyright (c) 2014 "Cowboy" Ben Alman
Licensed under the MIT license.