lodash 無法展平數組

Question

我正在嘗試取消嵌套當前使用此代碼的數組：

var mapped = _.flatMap(payload, ({GroupId,Learners}) =>
    _.map(Learners, LearnerId => ({GroupId:GroupId,Learner:LearnerId}))
);

然而值返回仍然產生和數組：例如

{"GroupId":1246574,"Learner":{"Forename":"George","Surname":Bob",,"StartDate":"2020-09-01","EndDate":"2021-08-27"}}

如何修改上面的腳本以僅返回 GroupId 和 Surname？

有效載荷的示例在這里：

var payload = 
{
    "GroupId": 1208864,
    "Code": "Ext-StuOth",
    "GroupType": "AcademicHouseGroup",
    "Learners": [
        {
            "LearnerId": 245218,
            "LearnerCode": "2009-0017",
            "Forename": "Sanelisiwe",
            "Surname": "Nazi-Angileh",
            "LearnerGroupLearnerId": 14719301,
            "StartDate": "2017-03-09",
            "EndDate": null
        },
        {
            "LearnerId": 246638,
            "LearnerCode": "2013-0076",
            "Forename": "Randal",
            "Surname": "Bodziarczyk",
            "LearnerGroupLearnerId": 14650361,
            "StartDate": "2017-02-20",
            "EndDate": null
        },
        {
            "LearnerId": 245253,
            "LearnerCode": "109056",
            "Forename": "Wafah",
            "Surname": "Dadisman",
            "LearnerGroupLearnerId": 14650360,
            "StartDate": "2017-02-20",
            "EndDate": null
        }
},{
            "GroupId": 1226419,
            "Code": "U6-JD",
            "GroupType": "RegistrationGroup",
            "Learners": [
                {
                    "LearnerId": 245507,
                    "LearnerCode": "110015",
                    "Forename": "Nahomy",
                    "Surname": "Osburn",
                    "LearnerGroupLearnerId": 14918706,
                    "StartDate": "2017-09-07",
                    "EndDate": "2018-07-31"
                },
                {
                    "LearnerId": 245994,
                    "LearnerCode": "111624",
                    "Forename": "Sherhona",
                    "Surname": "Dobritoiu",
                    "LearnerGroupLearnerId": 14707593,
                    "StartDate": "2017-08-01",
                    "EndDate": "2018-07-31"
                }
}

Answer 1

var result = _.flatMap(payload, ({GroupId, Learners}) => {
    return _.map(Learners, learner => ({GroupId, LearnerId: learner.LearnerId}))
})

Answer 2

它不是一個數組，它是一個JSON 對象（包含數組）

您可以按以下方式訪問訪問元素：

  console.log(payload.GroupId);
  var learners = payload.Learners;
  learners.forEach(function(learner){    
  console.log(learner.Surname);