javascript - 从数组中获取ID，存储它并在本地删除它

Question

我正在构建一个 Angular/Javascript/Ionic/Cordova 应用程序。

我有一个函数，我调用下面的数组，该数组存储为变量(existingEntries)

categories: Array [276]
 [0...99]
   0: Object
     id: 288
     exclude: false   
   1: Object
     id: 320
     exclude: true 

此函数会抓取该数组中的所有元素，以查看排除值是否设置为 true 或 false

    var existingEntries = $scope.categoryList;
    if(existingEntries == null) existingEntries = [];
        for (var i = 0; i < existingEntries.length; i++) {
            if (existingEntries[i]['exclude'] == true) {
                $scope.addLocalExcludedCategories(i);
            } else if (existingEntries[i]['exclude'] == false) {
                $scope.removeLocalExcludedCategories(i);
            }                       
    }

完成此操作后，将调用其他相关函数(addLocal.. 和 remove Local...)来存储 id。下面是 addLocal.. 函数，它可以工作，但是当我一遍又一遍地运行此代码时，我会得到重复项，并且我确信它可以编码得更好。我正在使用本地存储，因为我需要将数组保存在本地，但如果您有其他解决方案那就太好了。

    $scope.addLocalExcludedCategories = function(catID) {
    console.log("addLocalExcludedCategories Called")
    //Add Item to Excluded Categories Variable
    var existingEntries = JSON.parse(window.localStorage.getItem("ExcludedCategories"));                            
    if(existingEntries == null) existingEntries = [];

    var entryId = catID;
    var entry = {
        'id': entryId,
    };
    existingEntries.push(entry);        

    window.localStorage.setItem("ExcludedCategories", JSON.stringify(existingEntries));
    $scope.ExcludedCategories = window.localStorage.getItem("ExcludedCategories");      
}

这里还有一个删除函数，它没有按预期工作，因为我发现 id 的排除值设置为 true 而不是 false。

$scope.removeLocalExcludedCategories = function(catID) {    
console.log("removeLocalExcludedCategories Called")
    //Remove Item to Excluded Categories Variable
    var existingEntries = JSON.parse(window.localStorage.getItem("ExcludedCategories"));
    if(existingEntries == null) existingEntries = [];

    for (var i = 0; i < existingEntries.length; i++) {
        if (existingEntries[i]['id'] == catID) {
            console.log(i);
            existingEntries.splice(i, 1);
        }
    }
    //console.log("Remove Categories >>>");
    //console.log(existingEntries);
    window.localStorage.setItem("ExcludedCategories", JSON.stringify(existingEntries));
    $scope.ExcludedCategories = window.localStorage.getItem("ExcludedCategories");
    console.log($scope.ExcludedCategories);
}

希望这是有道理的，并提前致谢!

Answer 1

您没有检查 existingEntries 数组中是否已存在条目，这就是您受到欺骗的原因 试试这个代码...

$scope.addLocalExcludedCategories = function(catID) {
    console.log("addLocalExcludedCategories Called")
    //Add Item to Excluded Categories Variable
    var existingEntries = JSON.parse(window.localStorage.getItem("ExcludedCategories")) || [];

    var entryId = catID;
    var entry = {
        'id': entryId,
    };
    if(existingEntries.length > 0){
    existingEntries.forEach(function(entry){
     if(entry.id !== entry.id){
      existingEntries.push(entry); 
    }
    });