javascript - Ramda - 从数组中查找匹配的对象

Question

从以下两个列表 list1 和 list2 中，我需要从 list1 返回与 head 的值匹配的对象 和 tail 来自 list2。

我试图使用ramdajs来实现这一点。

const list1 = [ 
  { tail: 'A', head: 'B', distance: '5' },
  { tail: 'B', head: 'C', distance: '4' },
  { tail: 'C', head: 'D', distance: '8' },
  { tail: 'D', head: 'C', distance: '8' },
  { tail: 'D', head: 'E', distance: '6' },
  { tail: 'A', head: 'D', distance: '5' },
  { tail: 'C', head: 'E', distance: '2' },
  { tail: 'E', head: 'B', distance: '3' },
  { tail: 'A', head: 'E', distance: '7' } 
]

const list2 = [ { tail: 'A', head: 'B' }, { tail: 'B', head: 'C' } ]

// result should be [{ tail: 'A', head: 'B', distance: '5' },
// { tail: 'B', head: 'C', distance: '4' }] from list1

Answer 1

如果您想使用ramdajs，您可以使用innerJoin选择与谓词匹配的项目，如下所示:

const list1 = [ 
  { tail: 'A', head: 'B', distance: '5' },
  { tail: 'B', head: 'C', distance: '4' },
  { tail: 'C', head: 'D', distance: '8' },
  { tail: 'D', head: 'C', distance: '8' },
  { tail: 'D', head: 'E', distance: '6' },
  { tail: 'A', head: 'D', distance: '5' },
  { tail: 'C', head: 'E', distance: '2' },
  { tail: 'E', head: 'B', distance: '3' },
  { tail: 'A', head: 'E', distance: '7' } 
];

const list2 = [ { tail: 'A', head: 'B' }, { tail: 'B', head: 'C' } ];

const result = R.innerJoin(
  (item1, item2) => item1.tail === item2.tail && item1.head === item2.head,
  list1,
  list2
);

console.log(result);

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