index.js

void function(root){

  function defaults(options){
    var options = options || {}
    var min = options.min
    var max = options.max
    var integer = options.integer || false
    if ( min == null && max == null ) {
      min = 0
      max = 1
    } else if ( min == null ) {
      min = max - 1
    } else if ( max == null ) {
      max = min + 1
    }
    if ( max < min ) throw new Error('invalid options, max must be >= min')
    return {
      min:     min
    , max:     max
    , integer: integer
    }
  }

  function random(options){
    options = defaults(options)
    if ( options.max === options.min ) return options.min
    var r = Math.random() * (options.max - options.min + Number(!!options.integer)) + options.min
    return options.integer ? Math.floor(r) : r
  }

  function generator(options){
    options = defaults(options)
    return function(min, max, integer){
      options.min     = min != null ? min : options.min
      options.max     = max != null ? max : options.max
      options.integer = integer != null ? integer : options.integer
      return random(options)
    }
  }

  module.exports =  random
  module.exports.generator = generator
  module.exports.defaults = defaults
}(this)