arlib

arlib

Andras' Library of Handy Utilities

This is a placeholder for some of the code I've been working on that I want easy access to. Feel free to browse and use!

Contents

The components are all available with require('arlib'), or each component is loadable separately with eg require('arlib/tempnam').

tempnam

php tempnam equivalent, creates a filename that does not exist on the system. Like php, it also creates the file to prevent the name from being reused.

    var tempnam = require('arlib/tempnam');
    var filename = tempnam("/usr/tmp", "filename-prefix-");
    // /usr/tmp/filename-prefix-a7259b

getopt

traditional unix command option extractor, returns an object with the options set as properties. Like traditional unix, getopt only checks for option switches at the beginning of the argument list, before non-switch arguments. It recognizes '-' as a filename and '--' as the special marker that stops further argument scanning.

    var getopt = require('arlib/getopt').getopt;
    var options = getopt(process.argv, "f:h");
    // { f: 'filename', h: true }
    var options = getopt(process.argv, "(-file):(-help)");
    // {file: 'filename', help: true}

mongoid

very fast, light-weight mongodb compatible timestamped unique id generator. Can be used as a convenience function to return unique-ish (random) ids, or as an id factory configured with a unique system id to return locale-specific guaranteed unique ids.

    // convenience function, picks a random system id
    var mongoid = require('arlib').mongoid;
    id = mongoid();                 // 543f376340e2816497000001
    id = mongoid();                 // 543f376340e2816497000002

    // id factory, configured for the unique system identifier 1
    var MongoId = require('arlib').MongoId;
    var idFactory = new MongoId(1);
    id = idFactory.fetch();         // 543f3789000001649f000001
    id = idFactory.fetch();         // 543f3789000001649f000002

Fgets

synchronous line-at-a-time stream reader. Returns the next buffered line or the empty string "" if the buffer is currently empty. 3x faster than require('readline'), and works like C fgets(), it doesn't modify the input. Note: the caller must periodically yield with setImmediate or setTimeout to allow the buffer to fill.

    var fs = require('fs');
    var Fgets = require('arlib').Fgets;
    var fp = new Fgets(fs.createReadStream('/etc/motd', 'r'));
    // line = fp.fgets();

feof

returns true when fgets has no more lines to return

    var Fgets = require('arlib').Fgets;
    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
    })();

FileReader

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

    var FileReader = require('arlib').FileReader;
    var fp = new Fgets(new FileReader('/etc/motd'));
    // line = fp.fgets();