通过比较两个数组并动态添加一个键来生成一个数组

Question

我的应用程序从 API 接收数据并将其保存在 $scope.newz 中。

bookmarkData 是从 LocalStorage 加载的。

我正在比较 $scope.newz 和 $scope.bookmarkData 这两个数组的 contentId 的值。

我不知道如何保存bookmarkstate : true 仅用于匹配的数组项。

最后将匹配的记录添加到$scope.AllnewsList。

这是我的代码

if(data.Status.ResponseCode == 200)
  { 
    $("#fetchnews").hide();

    // $("#nodata").show();

    $("#sError").hide();

    //$scope.AllnewsList =  data.contents;

    $scope.newz = data.contents; 
    $scope.bookmarkData = JSON.parse(window.localStorage.getItem('bookmark'));

    for (var i=0; i < $scope.newz.length; i++)
    {
      for (var j=0; j < $scope.bookmarkData.data.length; j++) 
      {
        if ($scope.newz[i].ContentId == $scope.bookmarkData.data[j].ContentId)
          {
            // console.log($scope.newz[i].ContentId);
            $scope.bookmarkstate == true; 
          }
          else
          {
            $scope.bookmarkstate == false;
          }
      }
    }
    $scope.AllnewsList = $scope.newz;
  }

Answer 1

如果我理解正确，您希望注册每个newz，无论您是否至少有一个书签。

如果您想这样做，我建议您将 $scope.bookmarkstate 设置为与 newz 数组大小相同的数组。

这样，如果"newz" 数组中的相应单元格包含书签，您就可以在其每个单元格中注册。

if(data.Status.ResponseCode == 200)
    { 
       $scope.bookmarkstate = [];
       $("#fetchnews").hide();
       $("#sError").hide();
      $scope.newz = data.contents; 
      $scope.bookmarkData = JSON.parse(window.localStorage.getItem('bookmark'));
       for (var i=0; i < $scope.newz.length; i++)
        {
          for (var j=0; j < $scope.bookmarkData.data.length; j++) 
          {
              if ($scope.newz[i].ContentId == $scope.bookmarkData.data[j].ContentId)
               {
                 $scope.bookmarkstate[i] == true; 
              }
              else
              {

                 $scope.bookmarkstate[i] == false;
              }
          }
      }
       $scope.AllnewsList = $scope.newz;
   }

让我知道你的效果如何。 干杯。

Answer 2

假设您在评论中提到的键并假设动态数据，我以以下方式定义您的数组..

如果我误解了你的问题，请纠正我

var newz = [{contentId : 1, source : 'demoSrc1', title:'title1' },
{contentId : 2, source : 'demoSrc2', title:'title2' },
{contentId : 3, source : 'demoSrc3', title:'title3' },
{contentId : 4, source : 'demoSrc4', title:'title4' },
{contentId : 5, source : 'demoSrc5', title:'title5' },
{contentId : 6, source : 'demoSrc6', title:'title6' },
{contentId : 7, source : 'demoSrc7', title:'title7' },
{contentId : 8, source : 'demoSrc8', title:'title8' }];
//I defined your newz statically for simplicity.

var bookmarkData = [{contentId : 1, source : 'demoSrc1', title:'title1' },
{contentId : 4, source : 'demoSrc4', title:'title4' },
{contentId : 6, source : 'demoSrc6', title:'title6' },
{contentId : 8, source : 'demoSrc8', title:'title8' }];
//SIMILARLY id defined your bookmarkData statically.


var AllnewsList = [];


    for (var i=0; i <  newz.length; i++)
    {
      for (var j=0; j < bookmarkData.length; j++) 
      {
            if (newz[i].contentId == bookmarkData[j].contentId)
          {

            newz[i].bookmarkstate = true; 
            AllnewsList.push(newz[i]);
//            console.log(newz[i]);
          }
          else
          {
            newz[i].bookmarkstate = false;
          }
  //        console.log(newz[i].contentId);

      }
    }
console.log(AllnewsList);

Answer 3

Tip : You are not using assignment operator in your code to store status and i will recommend you to use
underscore for this tasks if you want to minimize lines of code.

If i understand you correctly the bookmarkstate array  will have true value for each news if news ContentId is equal to each bookmarkData ContentId else it will store false for each news.
var bookmarkstate = [];
var newz = [
    {
        id: 1,
        name: "first",
        ContentId: 3
    },

    {
        id: 2,
        name: "second",
        ContentId: 33
    },
    {
        id: 3,
        name: "third",
        ContentId: 3
    }

];
var bookmarkData = [
    {
        id: 1,
        name: "first",
        ContentId: 3
    },

    {
        id: 2,
        name: "second",
        ContentId: 33
    },
    {
        id: 3,
        name: "third",
        ContentId: 3
    }

];

for (var i = 0; i < newz.length; i++) {
    for (var j = 0; j < bookmarkData.length; j++) {
        if (newz[i].ContentId == bookmarkData[j].ContentId) {
            bookmarkstate[i] = true; // you were not using assignment operator
        } else {
            bookmarkstate[i] = false;// ou were not using assignment operator
        }

    }
}
console.log(bookmarkstate);