Question

我有一个

格式的JSON数据

[{
    "Heading1": [{
        "questionID": "q1",
        "questionTitle": "Question 1",
        "question": "This is question1",
        "status": 0,
        "files": [],
        "uploadType": "none"
    }, {
        "questionID": "q2",
        "questionTitle": "Question 2",
        "question": "This is question2",
        "status": 0,
        "files": [],
        "uploadType": "none"
    }]
}, {
    "Heading2": [{
        "questionID": "q3",
        "questionTitle": "Question 11",
        "question": "This is a question11",
        "status": 0,
        "files": [],
        "uploadType": "none"
    }]
}, {
    "Heading3": [{
        "questionID": "q4",
        "questionTitle": "Question 1",
        "question": "This is a question",
        "status": 0,
        "files": [],
        "uploadType": "none"
    }]
}]

我正在尝试以[{"Title":"Heading1"},{"Title":"Heading2"},{"Title":"Heading3"}]

的格式获取所有标题

我应该怎么做？

Answer 1

首先，如果您确实有JSON（例如，您的起点是一个字符串，例如来自ajax响应的字符串），则可以通过JSON.parse对其进行解析以获取对象数组。然后循环数组，并通过Object.keys(x)[0]从每个顶级对象中获取唯一键，并将其映射到所需形式的对象数组：

const json = '[{"Heading1":[{"questionID":"q1","questionTitle":"Question 1","question":"This is question1","status":0,"files":[],"uploadType":"none"},{"questionID":"q2","questionTitle":"Question 2","question":"This is question2","status":0,"files":[],"uploadType":"none"}]},{"Heading2":[{"questionID":"q3","questionTitle":"Question 11","question":"This is a question11","status":0,"files":[],"uploadType":"none"}]},{"Heading3":[{"questionID":"q4","questionTitle":"Question 1","question":"This is a question","status":0,"files":[],"uploadType":"none"}]}]';
const parsed = JSON.parse(json);
const result = parsed.map(entry => {
  return {Title: Object.keys(entry)[0]};
});
console.log(result);

map回调可以是一个简洁的箭头函数，但我认为使用上面的详细形式会更清楚。简洁的形式是：

const result = parsed.map(entry => ({Title: Object.keys(entry)[0]}));

请注意，以这种方式使用Object.keys只有在对象确实只有一个属性的情况下才是可靠的，如您所问的那样。如果它们具有多个属性，则Object.keys中数组中列出的属性的顺序未定义（即使在ES2015 +中，属性确实具有顺序-不需要Object.keys遵循该顺序[尽管它在我测试过的每个现代引擎上都可以使用]。

在React Native中获取JSON密钥数组

1 个答案: