javascript - 获取数组对象中第一个对象的键

Question

我正在尝试从一组对象中获取一组(不同的)键。

arr =[
   {id: 1, desc: "", name: "", objectives: Array(3), …},
   {id: 2, desc: "", name: "", objectives: Array(3), …},
   {id: 3, desc: "", name: "", objectives: Array(3), …},
   {id: 4, desc: "", name: "", objectives: Array(3), …},
]

期望的输出是 [id, desc, name, objectives]。我试过:

Object.keys(arr)[0]
// output [{id: 1, desc: "", name: "", objectives: Array(3), …}]

arr.flatMap(Object.key)
// output ["id", "desc", "name", "objectives", "id", "desc", "name", "objectives", "id", "desc", "name", "objectives", "id", "desc", "name", "objectives"]

如果我在搜索 SO 时错过了这个问题的答案，我很抱歉。非常感谢任何帮助。

Answer 1

您可以使用 Set 来清除重复项:

const arr = [
   {id: 1, desc: "", name: "", objectives: []},
   {id: 2, desc: "", name: "", objectives: []},
   {id: 3, desc: "", name: "", objectives: []},
   {id: 4, desc: "", name: "", objectives: []},
];

const keys = [...new Set(arr.flatMap(Object.keys))];

console.log(keys);