AngularJs显示过滤列表的第一个和最后一个

KingStakh 发表于 Dev

金斯塔克

在从数组中过滤空字符串后，仅显示第一个和最后一个重复的元素会有一些问题。

我的代码：

var myApp = angular.module('myApp', []);

myApp.controller("myCtrl", function ($scope, $window) {
    $scope.items = [
        { name: "item1", color: "green", form: "" },
        { name: "item2", color: "", form: "circle" },
        { name: "item3", color: "red", form: "" },
        { name: "item4", color: "", form: "oval" },
        { name: "item5", color: "blue", form: "" },
        { name: "item6", color: "", form: "square" },
        { name: "item7", color: "yellow", form: "" },
        { name: "item8", color: "", form: "rectangle" }     
    ];
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<body ng-app="myApp" ng-controller="myCtrl" class="ng-scope">
<div ng-repeat="item in items" ng-if="item.form == ''">
    {{item.name}}-{{item.color}}
</div>
<br />
<div ng-repeat="item in items" ng-if="item.color == ''">
    {{item.name}}-{{item.form}}
</div>
<br />
</body>

但我只需要显示列表中的第一和最后一个。前任。在第一个列表中：item1-green和item7-yellow（必须隐藏item3-red和item5-blue），第二个列表中的item2-circle和item8-rectangle。

维尼什

我为您的用例创建了自定义过滤器。基本上，过滤器将通过过滤传递的参数（形式和颜色）的空值来返回数组。

过滤后，您可以使用$first，并$last与ng-if只显示第一和最后一个元素。

请参阅下面的代码。

var myApp = angular.module('myApp', []);
  

  myApp.filter('customFilter', function() {
      return function(input, param) {
        if(input.length == 0) { return [];}
        var result = [];
        angular.forEach(input, function(item) {
          if(item[param] && item[param]!= '') {
            result.push(item);
          }
        });
        return result;
     }
  })

myApp.controller("myCtrl", function ($scope, $window) {
    $scope.items = [
        { name: "item1", color: "green", form: "" },
        { name: "item2", color: "", form: "circle" },
        { name: "item3", color: "red", form: "" },
        { name: "item4", color: "", form: "oval" },
        { name: "item5", color: "blue", form: "" },
        { name: "item6", color: "", form: "square" },
        { name: "item7", color: "yellow", form: "" },
        { name: "item8", color: "", form: "rectangle" }     
    ];
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<body ng-app="myApp" ng-controller="myCtrl" class="ng-scope">
<div ng-repeat="item in items | customFilter:'color'" ng-if="$first || $last">
    {{item.name}}-{{item.color}}
</div>
<br />
<div ng-repeat="item in items | customFilter:'form'" ng-if="$first || $last">
    {{item.name}}-{{item.form}}
</div>
<br />
</body>

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