Ramda - extract object from array

Question

I am trying to filter an array of objects with Ramda and it is working almost as I planned but I have one small issue. My result is array with one filtered object which is great but I need only object itself not array around it.

My example data set:

const principlesArray = [
  {
    id: 1,
    harvesterId: "1",
    title: "Principle1"
  },
  {
    id: 2,
    harvesterId: "2",
    title: "Principle2"
  },
]

And that is my Ramda query:

R.filter(R.propEq('harvesterId', '1'))(principlesArray)

As a result I get array with one filtered element but I need object itself:

[{"id":1,"harvesterId":"1","title":"Principle1"}]

Any help will be appreciated

Ori Drori · Accepted Answer · 2020-06-12 11:59:41Z

3

You can use R.find instead of R.filter, to get the first object found:

const principlesArray = [{"id":1,"harvesterId":"1","title":"Principle1"},{"id":2,"harvesterId":"2","title":"Principle2"}]

const result = R.find(R.propEq('harvesterId', '1'))(principlesArray)

console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.0/ramda.js"></script>

A more generic approach would be to create a function that takes a predicate used by R.where, pass the partially applied R.where to R.find, and then get the results by applying the function to the array:

const { pipe, where, find, equals } = R

const fn = pipe(where, find)

const principlesArray = [{"id":1,"harvesterId":"1","title":"Principle1"},{"id":2,"harvesterId":"2","title":"Principle2"}]

const result = fn({ harvesterId: equals('1') })(principlesArray)

console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.0/ramda.js"></script>

answered Jun 12, 2020 at 11:59

Ori Drori

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1 Comment

omygoodness Over a year ago

Using find instead filter was so obvious... In my case it should be enough. Thank you :)

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