Password strength directive for angular.

passwordstrength.js

.directive('checkStrength', function () {

		return {
			
			restrict: 'A',
			link: function(scope, element, attrs){
				function scorePassword(pass) {
					var score = 0;
					if (!pass)
						return score;

					// award every unique letter until 5 repetitions
					var letters = new Object();
					for (var i=0; i<pass.length; i++) {
						letters[pass[i]] = (letters[pass[i]] || 0) + 1;
						score += 5.0 / letters[pass[i]];
					}

					// bonus points for mixing it up
					var variations = {
						digits: /\d/.test(pass),
						lower: /[a-z]/.test(pass),
						upper: /[A-Z]/.test(pass),
						nonWords: /\W/.test(pass),
					}

					var variationCount = 0;
					for (var check in variations) {
						variationCount += (variations[check] == true) ? 1 : 0;
					}
					score += (variationCount - 1) * 10;

					return parseInt(score);
				}
				scope.$watch(attrs.checkStrength, function(value) {
					if(angular.isDefined(value)){

						if (scorePassword(value) > 80) {
							scope.strength = 'strong';
						} else if (scorePassword(value) > 60) {
							scope.strength = 'medium';
						} else {
							scope.strength = 'weak';
						}
					}
				});
			}
		};

	})