Node Ramda + find the object based on value

问题

Possible to get object based on the value?

In below sample json, the key name have type, so based on type value need to fetch the results.

For example if type='user' then fetch the result only for users object not for employee object.

Here I am struggling have both keys(users and employee), Could you please suggest to how to approach

var list =[
  {"doc":{"type":"user","Title":"test1","Relations":{"users":[{"name": "user1"},{"name": "user2"},{"name": "user3"}],"employee":[{"emp": "user2"}]}}},
  {"doc":{"type":"employee","Title":"test2","Relations":{"users":[{"name": "user1"}],"employee":[{"name": "emp1"},{"name": "emp2"},{"name": "emp3"}]}}}
];

const getDetails = R.chain(R.pipe(
  R.path(['doc', 'Relations']),
  R.pick(['users', 'employee']),
  R.values
))

const result = getDetails(list)

console.log(result)

<script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>

Current Output:

[[{"name": "user1"}, {"name": "user2"}, {"name": "user3"}], [{"emp": "user2"}], [{"name": "user1"}], [{"name": "emp1"}, {"name": "emp2"}, {"name": "emp3"}]]

Expecting output:

[[{"name": "user1"}, {"name": "user2"}, {"name": "user3"}], [{"name": "emp1"}, {"name": "emp2"}, {"name": "emp3"}]]

回答1:

You can make use of R.cond to branch logic based on a set of predicates, like whether type is user or employee in your example.

With this approach you will need to switch your R.chain to R.map to match your expected list, unless you want the extra flattening of the arrays.

const list = [
  {"doc":{"type":"user","Title":"test1","Relations":{"users":[{"name": "user1"},{"name": "user2"},{"name": "user3"}],"employee":[{"emp": "user2"}]}}},
  {"doc":{"type":"employee","Title":"test2","Relations":{"users":[{"name": "user1"}],"employee":[{"name": "emp1"},{"name": "emp2"},{"name": "emp3"}]}}}
]

const getDetails = R.map(R.pipe(
  R.prop('doc'),
  R.cond([
    [R.propEq('type', 'user'), R.path(['Relations', 'users'])],
    [R.propEq('type', 'employee'), R.path(['Relations', 'employee'])]
  ])
))

const expected = [[{"name": "user1"}, {"name": "user2"}, {"name": "user3"}], [{"name": "emp1"}, {"name": "emp2"}, {"name": "emp3"}]]

console.log(R.equals(expected, getDetails(list)))

<script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>

来源：https://stackoverflow.com/questions/51170414/node-ramda-find-the-object-based-on-value