demo-group-by.html

  <link rel="stylesheet" href="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.css">

  <button class="btn btn-default btn-xs" ng-click="ctrl.enable()">Enable ui-select</button>
  <button class="btn btn-default btn-xs" ng-click="ctrl.disable()">Disable ui-select</button>
  <button class="btn btn-default btn-xs" ng-click="ctrl.clear()">Clear ng-model</button>

  <h1>Group By</h1>
  <p>Selected: {{ctrl.person.selected}}</p>

  <h3>Grouped using a string <small><code>group-by="'country'"</code></small></h3>
  <ui-select ng-model="ctrl.person.selected" theme="select2" ng-disabled="ctrl.disabled" style="min-width: 300px;" title="Choose a person">
    <ui-select-match placeholder="Select a person in the list or search his name/age...">{{$select.selected.name}}</ui-select-match>
    <ui-select-choices group-by="'country'" repeat="person in ctrl.people | propsFilter: {name: $select.search, age: $select.search}">
      <div ng-bind-html="person.name | highlight: $select.search"></div>
      <small>
        email: {{person.email}}
        age: <span ng-bind-html="''+person.age | highlight: $select.search"></span>
      </small>
    </ui-select-choices>
    </ui-select>

  <h3>Grouped using a function <small><code>group-by="ctrl.someGroupFn"</code></small></h3>
  <ui-select ng-model="ctrl.person.selected" theme="select2" ng-disabled="ctrl.disabled" style="min-width: 300px;" title="Choose a person">
    <ui-select-match placeholder="Select a person in the list or search his name/age...">{{$select.selected.name}}</ui-select-match>
    <ui-select-choices group-by="ctrl.someGroupFn" repeat="person in ctrl.people | propsFilter: {name: $select.search, age: $select.search}">
      <div ng-bind-html="person.name | highlight: $select.search"></div>
      <small>
        email: {{person.email}}
        age: <span ng-bind-html="''+person.age | highlight: $select.search"></span>
      </small>
    </ui-select-choices>
    </ui-select>

  <h3>Regular</h3>
  <ui-select ng-model="ctrl.person.selected" theme="select2" ng-disabled="ctrl.disabled" style="min-width: 300px;" title="Choose a person">
    <ui-select-match placeholder="Select a person in the list or search his name/age...">{{$select.selected.name}}</ui-select-match>
    <ui-select-choices repeat="person in ctrl.people | propsFilter: {name: $select.search, age: $select.search}">
      <div ng-bind-html="person.name | highlight: $select.search"></div>
      <small>
        email: {{person.email}}
        age: <span ng-bind-html="''+person.age | highlight: $select.search"></span>
      </small>
    </ui-select-choices>
  </ui-select>