1.1.1 • Public • Published


    line-at-a-time stream reader and fast newline terminated data transport. 3x faster than require('readline'), and works like C fgets(), it doesn't modify the input. Reads and returns a million lines / second.


        var Fgets = require('qfgets');
        // line-at-a-time file reader
        function readfile(filename, callback) {
            var fp = new Fgets(filename);
            var contents = "";
            return readlines();
            function readlines() {
                try {
                    for (var i=0; i<20; i++) contents += fp.fgets();
                    if (fp.feof()) return callback(null, contents);
                    else setImmediate(readlines);
                catch (err) {
                    return callback(err);


    Fgets( stream )

    create a new file reader. Stream is any object with a read([numbytes], callback) method, or a string filename. If a filename, a FileReader object will be created to read the input.

        var Fgets = require('qfgets');
        var fp = new Fgets('/etc/motd');

    fp.fgets( )

    return the next buffered newline-terminated line, or "" if the buffer is currently empty. Will return the empty string "" when the buffer is being filled, as well as after end of file. Use feof() to distinguish. Note: the caller must periodically yield with setImmediate or setTimeout to allow the buffer to fill.

        var nextLine = fp.fgets();

    fp.feof( )

    returns true when fgets has no more lines to return

        var Fgets = require('qfgets');
        var fp = new Fgets('/etc/motd');        // use buit-in FileReader
        var contents = "";
        (function readfile() {
            for (var i=0; i<40; i++) contents += fp.fgets();
            if (!fp.feof()) setImmediate(readfile);     // yield periodically

    processLines( visitor(err, cb), callback(err, count) )

    Run all newline-terminated lines in the file through the visitor() function. Visitor is called with the line string and a callback, and should return via its callback an error to stop the processing. processLines() calls its callback with the final success status and the count of lines successfully visited.

    Fgets.FileReader( filepath, [options] )

    fast file reader to feed data to fgets. A smidge faster than a read stream created with a reasonable highWaterMark (50% faster than a stream created with defaults)


    • bufferSize - size of read buffer, default 409600

        var reader = new Fgets.FileReader('/etc/motd', {bufferSize: 100000});
        var fp = new Fgets(reader);



    npm i qfgets

    DownloadsWeekly Downloads






    Last publish


    • andrasq