ng-if indexOf with JSON Arrays

Question

我有一个JSON输出items- 显示我使用的单个项目ng-repeat="item in items".我可以使用访问当前登录的用户对象user

每个项目可以属于多个用户的愿望清单.如果用户将一个项目添加到他的心愿单,则user_id保存在其中item.wishlists

单个的JSON输出item看起来像这样:

{"id":1,"title":"This is a tile","wishlists":[{"user_id":2},{"user_id":3}]}

当我这样做,user.id我得到当前登录用户的ID.

现在我想在ng-if内部使用ng-repeat="item in items"来检查current_user是否已经将此项添加到他的愿望清单,然后向该用户显示"从愿望清单中删除"按钮而不是"添加到心愿单".

我的工作方法是:

<div ng-repeat="item in items">
  <h3>{{item.title}}</h3>
  <a href="" ng-click="addToWishlist(item)" ng-if="item.wishlists.indexOf(user.id) == -1">Wish</a>
  <a href="" ng-click="removeFromWishlist(item)" ng-if="item.wishlists.indexOf(user.id) > -1">Undo-Wish</a>
</div>

我可以像这样使用indexOf吗？或者,检查user.id是否在item.wishlists user_id中的正确angularJS方法是什么？

更新:

查看:(如果为true,则ctrl.hasWished将图标从'favorite'更改为'favorite_border'如果为false)

<div ng-repeat="item in items">
      <md-button class="md-icon-button feed-wish md-warn" aria-label="Wish" ng-click="ctrl.toggleWish(item)">
        <i class="material-icons">favorite{{ctrl.hasWished(item) ? '' : '_border' }}</i>
      </md-button> 
</div>

控制器:

  // Check if User has wished this item already: Should return true or false
  this.hasWished = function(item) {
    return item.wishlists.some(function(wishlist) {
      return wishlist.user_id === Auth._currentUser.id; // returns true if currently logged in user id is on wishlist
    });
  };

  this.toggleWish = function(item) {
    if (!this.hasWished) {
      this.hasWished = true;
      items.wish(item); // sends PUT request
      ToastService.show(item.product + ' added to Wish List');
    } else {
      this.hasWished = false;
      items.unWish(item); // sends DELETE request
      ToastService.show(item.product + ' removed from Wish List');
    }
  }

当我点击按钮,如果它的假前,它发出的PUT请求,我也得到了ToastService消息"添加...",如果我再次点击发送删除请求和ToastService消息"去掉..".但Icon并没有从"最爱"变为"favorite_border".当我重新加载页面时,会显示正确的图标.

我在控制台中也有此错误消息:

TypeError: Cannot read property 'id' of null
    at http://ruby-on-rails-140223.nitrousapp.com:3000/assets/auctions/auctionCtrl-f2cb59b8ad51e03a2264ef2c6e759a54.js?body=1:33:52
    at Array.some (native)
    at hasWished (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/auctions/auctionCtrl-f2cb59b8ad51e03a2264ef2c6e759a54.js?body=1:32:30)
    at fn (eval at <anonymous> (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:13323:15), <anonymous>:4:318)
    at Object.expressionInputWatch [as get] (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:14303:31)
    at Scope.$digest (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:15819:40)
    at Scope.$apply (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:16098:24)
    at done (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:10547:47)
    at completeRequest (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:10745:7)
    at XMLHttpRequest.requestLoaded (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:10686:9)

当点击这个错误时:

TypeError: v2.hasWished is not a function
    at fn (eval at <anonymous> (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:13323:15), <anonymous>:4:318)
    at Object.expressionInputWatch [as get] (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:14303:31)
    at Scope.$digest (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:15819:40)
    at Scope.$apply (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:16098:24)
    at HTMLButtonElement.<anonymous> (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular-touch/angular-touch-b4d02ed602708a1c93b51087222e0363.js?body=1:478:13)
    at HTMLButtonElement.eventHandler (http://ruby-on-rails-140223.nitrousapp.com:3000/assets/angular/angular-81b9b668c3f93c8ccb76b27ad984d9b6.js?body=1:3299:21)

Answer 1

过滤器应该起作用：

<div ng-repeat="item in items">
  <h3>{{item.title}}</h3>
  <a href="" ng-click="addToWishlist(item)" ng-if="!(item.wishlists|filter:{user_id:user.id}).length">Wish</a>
  <a href="" ng-click="removeFromWishlist(item)" ng-if="(item.wishlists|filter:{user_id:user.id}).length">Undo-Wish</a>
</div>