javascript - 通过字符串属性值查找对象数组中最长的字符串

Question

我目前有一个如下所示的数组:

var array = [
  {
    "title": "Ender's Game",
    "genre": "Science Fiction",
    "year": 2008
  },
  {
    "title": "Harry Potter and the Goblet of Fire",
    "genre": "fantasy",
    "year": 2002
  },
  {
    "title": "Pride and Predjudice",
    "genre": "romance",
    "year": 1980
  }
]

我想遍历这个数组并找到最长流派的长度。我想要这样的东西:

longestGenre(array);
15

我尝试了一些方法，包括以下内容:

var getLongest = (array, key) =>
{
  let r = Object.values(array).reduce((res, curr) =>
  {
      if (!Array.isArray(curr))
          return res;

      let newMax = curr.reduce(
          (r, c) => c[[key]] && (c[[key]].length > r.length) ? c[[key]] : r,
          ""
      );

      res = newMax.length > res.length ? newMax : res;
      return res;

  }, "");
  longest = r;
  return longest;
}

我尝试的另一种方法是:

  for (key in obj){
      if (!obj.hasOwnProperty(key)) continue;
          if (obj.key.length > longest)
              longest = obj.key.length;
  }

Answer 1

您不需要所有这些检查和嵌套循环，只需将数组映射到流派的长度，然后取最大值:

 const longestGenre = Math.max(...array.map(movie => movie.genre.length));

或动态:

const longest = (key, array) => Math.max(...array.map(it => it[key].length));

console.log(longest("genre", /*in*/ array));