discourse-custom-wizard/assets/javascripts/discourse/components/wizard-custom-inputs.js.es6

export default Ember.Component.extend({
  valuePlaceholder: 'admin.wizard.value',

  actions: {
    add() {
      if (!this.get('inputs')) {
        this.set('inputs', Ember.A());
      }
      this.get('inputs').pushObject(Ember.Object.create());
    },

    remove(input) {
      this.get('inputs').removeObject(input);
    }
  }
});