text: (function(angular, _) {
    class Finder {
      constructor(input, mappings, key) {
        this.input = input;
        this.mappings = mappings;
        this.key = key;
      }
  
      find() {
        var input = this.input,
            key = this.key;
  
        if (input === null) {
          return null;
        }
  
        return _.find(this.mappings, function(object) {
          return object[key] === input;
        });
      }
    }
  
    Finder.find = function(input, mappings, key) {
      return new Finder(input, mappings, key).find();
    };
  
    angular
      .module("plague_inc")
      .filter("select_transformer", function() {
        return Finder.find;
      });
  }(window.angular, window._));
  