javascript - 对于对象数组中每个对象中找到的值返回 true

Question

我正在尝试在我的 React 应用程序中实现一个点赞系统，但为此我需要知道当前LoggedIn 用户之前喜欢过哪些帖子，这样我就可以显示一个不喜欢的图标，反之亦然。

我的第一个想法是创建一个接收两个参数的小函数，即登录用户和 postId。这是函数:

const clickLike = (userId, postId) => {
    const match =
      timeline &&
      timeline.map(
        post =>
          post._id === postId && post.likes.filter(user => user === userId)
      );
    return match;
  };

前面的代码应该映射所有帖子，然后如果登录用户已经在 postId 对象上，则返回 true。这是我的 JSON 的样子:

"data": [
  {
      "status": "published",
      "_id": "5e5dcfc65104666e70558110",
      "text": "Mierda!",
      "user": {
          "_id": "5e0925629648903308163aeb",
          "username": "GodHimself",
          "avatar": "//www.gravatar.com/avatar/b62ddb6758fca61fb7a56381ac7cb07d?s=200&r=pg&d=mm",
          "bio": "I'm not God",
          "id": "5e0925629648903308163aeb"
      },
      "likes": [
          {
              "_id": "5e76bc5fd3266e125c2dc4b9",
              "user": "5e0925629648903308163aeb"
          },
      ],
      "id": "5e5dcfc65104666e70558110"
  },
  {
      "status": "published",
      "_id": "5e4a08dc4c1f0d2394f28d8e",
      "text": "Initial D!",
      "user": {
          "_id": "5e0925629648903308163aeb",
          "username": "GodHimself",
          "avatar": "//www.gravatar.com/avatar/b62ddb6758fca61fb7a56381ac7cb07d?s=200&r=pg&d=mm",
          "bio": "I'm not God",
          "id": "5e0925629648903308163aeb"
      },
      "likes": [],
      "id": "5e4a08dc4c1f0d2394f28d8e"
  },
  {
      "status": "published",
      "_id": "5e4a08584c1f0d2394f28d8d",
      "text": "Berserk Bois!",
      "user": {
          "_id": "5e0925629648903308163aeb",
          "username": "GodHimself",
          "avatar": "//www.gravatar.com/avatar/b62ddb6758fca61fb7a56381ac7cb07d?s=200&r=pg&d=mm",
          "bio": "I'm not God",
          "id": "5e0925629648903308163aeb"
      },
      "likes": [
          {
              "_id": "5e4b5c889861ad1cf8b67bbb",
              "user": "5e0925629648903308163aeb"
          },
          {
              "_id": "5e4b5ca59861ad1cf8b67bbc",
              "user": "5e0925629648903308163aeb"
          }
      ],
      "id": "5e4a08584c1f0d2394f28d8d"
  }
]

到目前为止，代码在任何单个帖子中都会返回 true，即使是那些没有收到点赞的帖子。

如有任何帮助，我们将不胜感激。

Answer 1

使用Array.prototype.some()

const clickLike = (userId, postId) => {
  return data.some(x => x._id === postId && x.likes.some(y => y._id === userId));
};

  const data = [
    {
      status: "published",
      _id: "5e5dcfc65104666e70558110",
      text: "Mierda!",
      user: {
        _id: "5e0925629648903308163aeb",
        username: "GodHimself",
        avatar:
          "//www.gravatar.com/avatar/b62ddb6758fca61fb7a56381ac7cb07d?s=200&r=pg&d=mm",
        bio: "I'm not God",
        id: "5e0925629648903308163aeb"
      },
      likes: [
        {
          _id: "5e76bc5fd3266e125c2dc4b9",
          user: "5e0925629648903308163aeb"
        }
      ],
      id: "5e5dcfc65104666e70558110"
    }
  ];
  const clickLike = (userId, postId) => {
    return data.some(x => x._id === postId && x.likes.some(y => y._id === userId));
  };
  console.log(
    clickLike("5e76bc5fd3266e125c2dc4b9", "5e5dcfc65104666e70558110"),
    clickLike("xxx", "5e5dcfc65104666e70558110"),
    clickLike("5e76bc5fd3266e125c2dc4b9", "xxx"),
    clickLike("xxx", "xxx")
  );