如何使用Ramda.js映射对象值并仅采用第一个元素？

Question

I have input like that:

{
  a: [obj1, obj2, obj3...],
  b: [obj1, obj2, obj3...],
  c: [obj1, obj2, obj3...]
}

I want to have that output (only first object from array for every key)

{
  a: [obj1],
  b: [obj1],
  c: [obj1]
}

I want to do it using ramda.js

Answer 1

The simplest answer is just map(head, obj) , or if you want a reusable function, map(head) .

You can see this in action on the Ramda REPL .

Answer 2

const data = {
  a: [obj1, obj2, obj3],
  b: [obj1, obj2, obj3],
  b: [obj1, obj2, obj3]
}

const updatedData = R.mapObjIndexed( value => ([value[0]]), data)

(This exact code won't work because obj1 , obj2 , and obj3 aren't defined)