迭代 JSON 格式的对象数组并修改和扩展它，最好使用 Underscore.js

Question

我从数据库中以 JSON 格式检索数据并分配给一个变量 - 'var tabs'.

格式化后的JSON如下：

[{
    "TAB_ID": "1",
    "TAB_NAME": "TAB ONE",
    "TAB_DISPLAY": "1",
    "QUESTIONS": [{
        "QUESTION_ID": 1,
        "QUESTION": "Question number one",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 2,
        "QUESTION": "Question number two",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 3,
        "QUESTION": "Question number six",
        "ANSWER": ""
    }]
}, {
    "TAB_ID": "1",
    "TAB_NAME": "TAB ONE",
    "TAB_DISPLAY": "1",
    "QUESTIONS": [{
        "QUESTION_ID": 1,
        "QUESTION": "Question number one",
        "ANSWER": "Some Other Answer"
    }, {
        "QUESTION_ID": 2,
        "QUESTION": "Question number two",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 3,
        "QUESTION": "Question number six",
        "ANSWER": "Some Still Different Answer"
    }]
}]

我需要遍历数组并执行以下操作：

对于 TAB 中的每个问题，如果问题有答案，我需要在问题中添加额外的 key/value of "HAS_ANSWER": "1"。

    {
        "QUESTION_ID": 1,
        "QUESTION": "Question number one",
        "ANSWER": "Some Other Answer",
        "HAS_ANSWER": "1"
    }

我花了几个小时阅读帖子、查看示例代码和阅读 Underscore 文档，我知道这应该相当简单，但我不知道如何解决这个问题。

我的理解是我可能想使用嵌套的 _.map 函数，但是我看过的所有示例 return 对象数组的子集，而不是修改和扩展一个，我需要得到完全相同格式的 JSON 数据（对象数组），但有上面提到的更改和添加。

如有任何帮助，我们将不胜感激。

更新：

使用这个：

data = _.map(data, obj => _.map(obj.QUESTIONS, q => {
    if (q.ANSWER) {
        q.HAS_ANSWER = 1;
    }
    return q;
}));

这会遍历问题，并相应地修改它们，但是 returned 对象会删除外层数据 - 它只是 return 一个问题数组，并且不会保留TAB 数据：

    "TAB_ID": "1",
    "TAB_NAME": "TAB ONE",
    "TAB_DISPLAY": "1",

解决方案是在外部数组上使用_.each，在内部数组上使用_.map。

data = _.each(data, obj => _.map(obj.QUESTIONS, q => {
    if (q.ANSWER) {
        q.HAS_ANSWER = 1;
    }
    return q;
}));

注意：此 => 语法仅适用于 Javascript 的较新实现，目前在 Safari / Webkit 中不受支持，因此请改用此语法以获得更好的兼容性

data = _.each(data, function(obj){
    _.map(obj.QUESTIONS, function(q){
       if (q.ANSWER) {
           q.HAS_ANSWER = 1;
       }
       return q;
    });
});

这完全符合我的需要。

Answer 1

这可以使用普通 JavaScript、Array#map、

来完成

// Iterate over data
data = data.map(obj => obj.QUESTIONS.map(q => {
    // If question has answer, then add `HAS_ANSWER` property
    if (q.ANSWER) {
        q.HAS_ANSWER = 1;
    }

    // Update question object
    return q;
}));

var data = [{
    "TAB_ID": "1",
    "TAB_NAME": "TAB ONE",
    "TAB_DISPLAY": "1",
    "QUESTIONS": [{
        "QUESTION_ID": 1,
        "QUESTION": "Question number one",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 2,
        "QUESTION": "Question number two",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 3,
        "QUESTION": "Question number six",
        "ANSWER": ""
    }]
}, {
    "TAB_ID": "1",
    "TAB_NAME": "TAB ONE",
    "TAB_DISPLAY": "1",
    "QUESTIONS": [{
        "QUESTION_ID": 1,
        "QUESTION": "Question number one",
        "ANSWER": "Some Other Answer"
    }, {
        "QUESTION_ID": 2,
        "QUESTION": "Question number two",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 3,
        "QUESTION": "Question number six",
        "ANSWER": "Some Still Different Answer"
    }]
}];

data = data.map(obj => obj.QUESTIONS.map(q => {
    if (q.ANSWER) {
        q.HAS_ANSWER = 1;
    }
    return q;
}));

console.log(data);
document.getElementById('output').innerHTML = JSON.stringify(data, 0, 4);

<pre id="output"></pre>

Underscore/Lodash

中的相同代码

data = _.map(data, obj => _.map(obj.QUESTIONS, q => {
    if (q.ANSWER) {
        q.HAS_ANSWER = 1;
    }
    return q;
}));

Answer 2

使用标准 Javascript 的 Array.prototype.forEach() 方法，它可能看起来像这样：

tabs.forEach(tab => {
  tab['QUESTIONS'].forEach(question => {
    if (question['ANSWER']) {
      question['HAS_ANSWER'] = 1;
    }
  });
});

var tabs = [{
    "TAB_ID": "1",
    "TAB_NAME": "TAB ONE",
    "TAB_DISPLAY": "1",
    "QUESTIONS": [{
        "QUESTION_ID": 1,
        "QUESTION": "Question number one",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 2,
        "QUESTION": "Question number two",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 3,
        "QUESTION": "Question number six",
        "ANSWER": ""
    }]
}, {
    "TAB_ID": "1",
    "TAB_NAME": "TAB ONE",
    "TAB_DISPLAY": "1",
    "QUESTIONS": [{
        "QUESTION_ID": 1,
        "QUESTION": "Question number one",
        "ANSWER": "Some Other Answer"
    }, {
        "QUESTION_ID": 2,
        "QUESTION": "Question number two",
        "ANSWER": ""
    }, {
        "QUESTION_ID": 3,
        "QUESTION": "Question number six",
        "ANSWER": "Some Still Different Answer"
    }]
}];

tabs.forEach(tab => {
  tab['QUESTIONS'].forEach(question => {
    if (question['ANSWER']) {
      question['HAS_ANSWER'] = 1;
    }
  });
});

console.log(tabs);

这种方法修改了数据。

迭代 JSON 格式的对象数组并修改和扩展它，最好使用 Underscore.js

Iterate over JSON formatted array of objects and modify and extend it, preferably using Underscore.js

javascript

arrays

json

iterator

underscore.js