Knockout.js model inheritance

DRY. If you are copy pasting your model methods/properties etc - you are on wrong way. Just inherit them from base model. Here is example:
<!DOCTYPE html>
<html>
  <head>
    <title>inheritance simple</title>
    <meta charset="utf-8" />
  </head>
  <body>
    <div class="container">
      <div data-bind="foreach: items">
        <p data-bind="text: toString()"></p>
      </div>
    </div>

    <script type="text/javascript" src="components/jquery/jquery.js"></script>
    <script type="text/javascript" src="components/knockout/build/output/knockout-latest.debug.js"></script>

    <script type="text/javascript">
      // Base model, that will be inherited
      // notice that options are provided as object, rather than simple arguments
      function QuestionBaseModel(options) {
        this.id = ko.observable()
        this.name = ko.observable()
        this.importance = ko.observable()
        this.importanceOptions = ['Non important', 'Semi important', 'Important']
        this.answer = ko.observable()

        // found at: http://stackoverflow.com/questions/10520400/knockout-issue-with-prototypical-inheritance
        this.init = function (options) {
          if (options) {
            for (key in options) {
              if (typeof this[key] === 'function') {
                this[key](options[key])
              } else {
                this[key] = options[key]
              }
            }
            //if(options.id) this.id(options.id);
            //if(options.name) this.name(options.name);
            //if(options.importance) this.importance(options.importance);
            //if(options.answer) this.answer(options.answer);
          }
        }
        this.init.apply(this, arguments) // apply given options
      }

      function QuestionExperienceModel(options) {
        this.answerOptions = ['little', '2+ years', 'huge'] // provide available answers

        this.toString = function () {
          return ko.toJSON(this)
        }

        this.init.apply(this, arguments) // apply given options
      }
      QuestionExperienceModel.prototype = new QuestionBaseModel() // inherit from base model

      function QuestionLanguageModel(options) {
        this.language = ko.observable(options.language) // additional field
        this.languageOptions = ['English', 'Ukrainian'] // and its options
        this.answerOptions = ['little', 'good', 'carrier'] // provide available answers

        // override name, so it is no longer writable
        this.name = ko.computed(function () {
          return 'Your knowledge of ' + this.language()
        }, this)

        this.toString = function () {
          return ko.toJSON(this)
        }

        this.init.apply(this, arguments) // apply given options
      }
      QuestionLanguageModel.prototype = new QuestionBaseModel() // inherit from base model

      function List() {
        var self = this

        self.items = ko.observableArray([
          new QuestionExperienceModel({ id: 1, name: 'Your experience in JS', importance: 'Important', answer: '2+ years' }),
          new QuestionLanguageModel({ id: 2, importance: 'Semi important', answer: 'good', language: 'Ukrainian' })
        ])
      }

      ko.applyBindings(new List())
    </script>
  </body>
</html>