Convert a Node.JS Readable Stream into a Line Buffered Input Stream
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Convert a Node.JS Readable Stream into a Line Buffered Input Stream


npm install line-input-stream


Like Readable Stream with a line event.

var LineInputStream = require('line-input-stream'),
    fs = require('fs');

var stream = LineInputStream(fs.createReadStream("foo.txt", { flags: "r" }));
stream.setDelimiter("\n");	// optional string, defaults to "\n"

stream.on("error", function(err) {

stream.on("data", function(chunk) {
		// You don't need to use this event

stream.on("line", function(line) {
		// Sends you lines from the stream delimited by delimiter

stream.on("end", function() {
		// No more data, all line events emitted before this event

stream.on("close", function() {
		// Same as ReadableStream's close event

if(stream.readable) {
	console.log("stream is readable");

// Also available: pause(), resume(), destroy(), pipe()

You can also attach listeners to any event specific to the underlying stream, ie, you can listen to the open event for streams created by fs.createReadStream() or the connect event for Net streams.

A side effect of this is that you can add a listener for any junk string and LineInputStream will pretend that it worked. The event listener may never be called though.

Caveats & Notes

  • Calling pause() might not stop line events from firing immediately. It will stop reading of data from the underlying stream, but any data that has already been read will still be split into lines and a line event will be fired for each of them.
  • The delimiter is not included in the line passed to the line handler
  • Even though this is called line-input-stream, you can delimit by anything, so for example, setting delimiter to "\n\n" will read by paragraph (sort of).
  • You can set the delimiter to a regular expression, which let's you do cool things like drop multiple blank lines: /[\r\n]+/
  • All methods return this, so can be chained


Philip Tellis @bluesmoon


(Apache License)[]