Angular1 custom filters

angular-filter-utils.js

angular.module('myApp', [])
/**
 * concat
 * transforms array [a,b,c] to a template string list 'a,b,c'
 * */
 .filter('concat', function() {
      return function(input, property) {
          var out = '';
          for (var i = 0; i < input.length; i++) {
              out += input[i][property] ? input[i][property] : input[i];
              if (i < (input.length - 1)) out += ', ';
          }
          return out;
      };
  })
/**
 * placeholder
 * shows a placeholder in the template if the main value is undefined
 * */
.filter('placeholder', function() {
  return function(input, property) {
      return (input == undefined || input == '') ? property : input;
  };
})