Custom Node.js Validator - arrayOf(size, regex) - Provides the ability to validate that a request value is an array of a given size where each element matches the regex pattern provided. Uses underscore. Designed for a node.js API path where 'date=2012-11-01,2012-12-01' will be used for a date filter into Mongo.

Validator.prototype.arrayOf(size, regex)

// This is a custom validator that will ensure that 
// the value is an array of two elements where each
// element matches the same regex format.
var _ = reqquire('underscore');

var simpleDateRegex = new RegExp("^[0-9]{4}\-(0[1-9]|1[012])\-(0[1-9]|[12][0-9]|3[01])");

Validator.prototype.arrayOf = function(size, regex) {

    // Split the string into an array.

    var opts = this.str.split(',');

    // Check the size is correct.
    if (opts.length != size ) {
      this.error(this.msg + ', Missing Date values.');
    }

    // Is the regex provides is a string, create a new RegExp

    if (!regex instanceof RegExp) regex = new RegExp(regex);
 
    // Use underscore to determine if which elements pass the regex.
    var passed = _.filter(opts, function(o) { return regex.test(o) });

    // Generate an error is the expected and the passed do not match.
    if (passed.length != opts.length) {
      this.error(this.msg + ', One or more do not match format');
    }

    return this; //Allow method chaining
}

/*

   // Sample Usage: This is used in an express route to ensure that a query value will 
   // meet the required format pattern. Basically two YYYY-MM-DD, coma separted.

   var v = new Validator();
   v.check(req.urlparams.date, 'Invalid Array of Dates (Requires: YYYY-MM-DD,YYYY-MM-DD)').arrayOf(2, simpleDateRegex);

   if (v.getErrors().length > 0) {
     res.send( JSON.stringify({ status: false, errors: v.getErrors()}), 200);
     return;
   }

*/

// T: 1/15/2012