nid.js

/* Copyright (c) 2013 Richard Rodger, MIT License */
"use strict";


/* Module API:
 * var nid = require('nid')
 * nid() // returns new random id as string
 * nid({options}) // returns new nid function that generates ids using options
 *
 * options are:
 *   length: number of chars in id
 *   alphabet: alphabet to take chars from randomly
 *   hex, HEX: alphabet is hexadecimal, lower or upper case respectively (overrides alphabet)
 *   exclude,curses: (exlude overrides)
 *     array of strings - excluded if contained in id
 *     string: comma-separated list of curses
 *     regexp: excluded if matches
 *     function: return true if exluded, first arg is id
 *
 */


var defaults = {
    length: 6,
    alphabet: '0123456789abcdefghijklmnopqrstuvwxyz',

    // function hidecurse(s) {o='';for(i=0; i<s.length; i++){o+='\\x'+(s.charCodeAt(i).toString(16).toUpperCase())} return o; }
    curses: [
        '\x66\x75\x63\x6B',
        '\x73\x68\x69\x74',
        '\x70\x69\x73\x73',
        '\x63\x75\x6E\x74',
        '\x74\x69\x74\x73',
        '\x6E\x69\x67\x67\x65\x72',
        '\x63\x6F\x63\x6B\x73\x75\x63\x6B\x65\x72',
        '\x6D\x6F\x74\x68\x65\x72\x66\x75\x63\x6B\x65\x72',
        '\\x66\\x72\\x61\\x63\\x6B',
        '\\x66\\x72\\x61\\x6B'
    ],

}


var default_cursed = cursing(defaults.curses)

    function cursing(curses) {
        var typestr = Object.prototype.toString.call(curses).substring(8)

        if ('String]' == typestr) {
            curses = curses.split(/\s*,\s*/)
        }

        if (Array.isArray(curses)) {
            return function (code) {
                var codelower = code.toLowerCase()
                for (var i = 0; i < curses.length; i++) {
                    if (-1 != codelower.indexOf(curses[i])) {
                        return true
                    }
                }
            }
        } else {
            if ('Function]' == typestr) {
                return curses
            } else if ('RegExp]' == typestr) {
                return function (code) {
                    return !!code.match(curses)
                }
            } else return function () {
                return false
            }
        }
    }


    function generate(opts) {
        var length = defaults.length
        var alphabet = defaults.alphabet
        var cursed = default_cursed

        if (opts) {
            length = opts.length || length
            alphabet = opts.alphabet || alphabet
            cursed = opts.curses ? cursing(opts.curses) : cursed
        }

        var code = null,
            numchars = alphabet.length

            do {
                var time = new Date().getTime()
                var sb = []
                for (var i = 0; i < length; i++) {
                    var c = Math.floor((time * Math.random()) % numchars)
                    sb.push(alphabet[c])
                }
                code = sb.join('')
            }
            while (cursed(code))

            return code
    }


    function make(opts) {
        ['length', 'alphabet', 'curses'].forEach(function (setting) {
            opts[setting] = (void 0 === opts[setting]) ? defaults[setting] : opts[setting]
        })

        if (opts.hex) {
            opts.alphabet = '0123456789abcdef'
        } else if (opts.HEX) {
            opts.alphabet = '0123456789ABCDEF'
        }

        // exclude overrides curses
        opts.curses = opts.exclude || opts.curses

        return function () {
            return generate(opts)
        }
    }


    function nid() {
        var arg0 = arguments[0]
        if (arg0) {
            var typestr = Object.prototype.toString.call(arg0).substring(8)

            if ("Number]" === typestr) {
                return generate({
                    length: arg0
                })
            } else if ("Object]" === typestr) {
                return make(arg0)
            } else return generate();
        }


        return generate()
    }

nid.__defaults = defaults


module.exports = nid