角度UI选择，唯一值预先选择数组

Question

假设我想要编辑一个现有实体，该实体具有一组值，这些值也是可选值的一部分。例如

var preSelectedLanguages = [
    {id: 2, iso: "de"},
    {id: 3, iso: "fr"}
]
var languages = [
    {id: 1, iso: "en"},
    {id: 2, iso: "de"},
    {id: 3, iso: "fr"},
    {id: 4, iso: "it"},
    {id: 5, iso: "us"}
]

我的ui选择指令类似于：

<ui-select multiple ng-model="preSelectedLanguages">
    <ui-select-match placeholder="Select language...">
        {{$item.iso}}
    </ui-select-match>
    <ui-select-choices repeat="l in languages track by language.id">
        {{language.iso}}
    </ui-select-choices>
</ui-select>

然而，ui-select-choices选项列表似乎无法删除重复项，即使我使用了track by language.id。

知道如何正确地做到这一点吗？

Answer 1

它以这种方式对我有效

<ui-select multiple ng-model="preSelectedLanguages">
    <ui-select-match placeholder="Select language...">
        {{$item.iso}}
    </ui-select-match>
    <ui-select-choices repeat="l in languages track by l.id">
        {{l.iso}}
    </ui-select-choices>
</ui-select>