Question

有人可以帮助我解决这个问题吗？

const Users = ({ users, loading }) => {
  if (loading) {
    return <Spinner />
  } else {
    return (
      <div style={userStyle}>
        {users.map((user) => (
          <UserItem key={users.id} user={user} />
        ))}
      </div>
    )
  }
}

Answer 1

在地图前使用conditional operator &&

const Users = ({ users, loading }) => {
  if (loading) {
    return <Spinner />
  } else {
    return (
      <div style={userStyle}>
        {users && users.map((user) => (
          <UserItem key={user.id} user={user} />
        ))}
      </div>
    )
  }
}

Answer 2

在地图内，您应该使用用户而不是用户，这样代码将是

{ users.map((user) => (
          <UserItem key={user.id} user={user} />
))}

Because, you are passing user as a argument for callback function not users.

×TypeError：无法读取未定义的属性“ map”。发现错误

2 个答案: