javascript - 使用 Jquery 检查 Javascript 对象中是否存在某些内容

Question

所以我有以下由服务器生成的 javascript 对象。该对象称为 $scope.activityResults

        [{
            id: 2010,
            updateId: 1,
            userId: 2,
            points: 10
        }, {
            id: 2011,
            updateId: 2,
            userId: 3,
            points: 100
        }];

然后我有一个新创建的项目，我想确定对象中是否存在 userId。如果 userId 存在，我想做 X，如果它们不存在，我想做 Y。

var newResult = {
            id: 0,
            updateId: 3,
            userId: 10,
            competitionId: "2014354864",
            result: $scope.activityPointsValue, 
            time: new Date()
        }

我正在努力找出最好的方法来检查对象中是否已存在 userId。

希望得到一些帮助。

if (newResult.userId exists in $scope.activityResults)) { //This line needs the help :)
            console.log("You already have some points");

        } else {
            console.log("Didnt find you, adding new row :)");
        }

Answer 1

最简单的方法是通过用户 ID 索引 scope.activityResults 数组。之后是简单的索引检查:

scope.activityResults[2]  = {
        id: 2010,
        updateId: 1,
        userId: 2,
        points: 10
};
scope.activityResults[3] = {
        id: 2011,
        updateId: 2,
        userId: 3,
        points: 100
};

var newResult = {
        id: 0,
        updateId: 3,
        userId:33,
        competitionId: "2014354864",
        result: scope.activityPointsValue,
        time: new Date()
};

if (scope.activityResults.hasOwnProperty(newResult.userId)) { //This line needs the help :)
    console.log("You already have some points");
} else {
    console.log("Didnt find you, adding new row :)");
}