如何格式化JSON对象数组（JavaScript）

Question

我在一个艰苦的要求中挣扎，我不知道该如何应对

我收到了一个数组，如下所示：

[{
    "student": "21_A_1",
    "sport": "badminton"
}, {
    "student": "21_C_1",
    "sport": "badminton"
}, {
    "student": "21_A_2",
    "sport": "badminton"
}, {
    "student": "21_B_1",
    "sport": "football"
}, {
    "student": "21_A_2",
    "sport": "football"
}]

要求：将其转换为以下格式的数组：

[{
    "student": "21_A_1",
    "sport": ["badminton"]
}, {
    "student": "21_C_1",
    "sport": ["badminton"]
}, {
    "student": "21_A_2",
    "sport": ["badminton","football"]
}, {
    "student": "21_B_1",
    "sport": ["football"]
}]

我发现lodash库具有“ group by”功能，返回的结果非常接近，但不符合预期：

_.groupBy(array, 'student');

结果：

{
    "21_A_1": [{
        "student": "21_A_1",
        "sport": "badminton"
    }],
    "21_C_1": [{
        "student": "21_C_1",
        "sport": "badminton"
    }],
    "21_A_2": [{
        "student": "21_A_2",
        "sport": "badminton"
    }, {
        "student": "21_A_2",
        "sport": "football"
    }],
    "21_B_1": [{
        "student": "21_B_1",
        "sport": "football"
    }]
}

任何建议都非常感谢。

Answer 1

我们可以使用数组的“ .reduce”功能并汇总结果，如下所示

 var test = [{ "student": "21_A_1", "sport": "badminton" }, { "student": "21_C_1", "sport": "badminton" }, { "student": "21_A_2", "sport": "badminton" }, { "student": "21_B_1", "sport": "football" }, { "student": "21_A_2", "sport": "football" }] const result = test.reduce((res,x)=>{ res[x.student] = res[x.student] || { student:x.student,sport:[]} res[x.student].sport.push(x.sport) return res; },{}) console.log(result) 

Answer 2

您需要将分组项目与其sport属性进行映射，并使用分组信息构建新对象。

 var array = [{ student: "21_A_1", sport: "badminton" }, { student: "21_C_1", sport: "badminton" }, { student: "21_A_2", sport: "badminton" }, { student: "21_B_1", sport: "football" }, { student: "21_A_2", sport: "football" }], grouped = _(array) .groupBy('student') .map((group, student) => ({ student, sport: _.map(group, 'sport') })) .value(); console.log(grouped); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.15.0/lodash.min.js"></script> 

Answer 3

结合使用Array.prototype.reduce（）与Object.values（） ：

 const data = [{"student": "21_A_1","sport": "badminton"}, {"student": "21_C_1","sport": "badminton"}, {"student": "21_A_2","sport": "badminton"}, {"student": "21_B_1","sport": "football"}, {"student": "21_A_2","sport": "football"}]; const result = Object.values( data.reduce((a, c) => ((a[c.student] = a[c.student] || {student: c.student, sport: []}).sport.push(c.sport), a), {}) ); console.log(result);