Fimp

Functional Immutable Programming

Fimp helps you work with Immutable.js data structures in a more functional way. Think of it as Ramda or lodash/fp for Immutable.

Documentation

Fimp provides composable, curried, data-last functions that work with immutable objects. If you are used to functional programming you are hopefully thinking "Nice, this makes sense, I can use this". If not, you might be thinking "Why would I want this?".

The aim of Fimp is to help you write cleaner, more understandable code. Composable functions makes it easier to create more complex functions by combining smaller building blocks. this article, explaining the rationale behind Ramda applies to Fimp as well. The only difference is that Fimp is built for use with Immutable data structures, whereas Ramda is used with plain javascript object.

The following functions are supported:

compose

  const add5 = map((a) => a + 5)
  const filterEven = filter((a) => !(a % 2))
  const sum = reduce((total, a) => a + total, 0)
  const addFilterAndSum = compose(sum, filterEven, add5)

  addFilterAndSum(fromJS([1, 2, 3]) // 14

concat

  const concat456 = concat(fromJS([4, 5, 6]))
  concat456(fromJS([1, 2, 3])).toJS() // [1, 2, 3, 4, 5, 6]

contains

  const containsA = contains('a')
  containsA(fromJS(['a', 'b', 'c'])) // true

curry

  const subtract = curry((a, b) => b - a)
  const subtract2 = subtract(2)
  subtract2(3) // 1
  subtract(2, 3) // 1

entrySeq

  entrySeq(fromJS({a: 'foo', b: 'bar', c: 'baz'})).toJS()
  // [['a', 'foo'], ['b', 'bar'], ['c', 'baz']]

every

  const allEven = every(isEven)
  allEven(fromJS([1, 4, 8])) // false
  allEven(fromJS([2, 4, 100])) // true

filter

  const filterEven = filter(isEven)
  filterEven(fromJS([1, 2, 3, 4, 5, 6, 7, 8])).toJS() // [2, 4, 6, 8]

find

  const findEven = find(isEven)
  findEven(fromJS([1, 4, 3])) // 4

flatten

  const shallowFlatten = flatten(true)
  shallowFlatten(fromJS([1, 2, [3, 4, [5, 6]]])) // List [1, 2, 3, 4, [5, 6]]
  })

  const deeperFlatten = flatten(2)
  deeperFlatten(fromJS([1, 2, [3, 4, [5, [6]]]])) // List [1, 2, 3, 4, 5, [6]]
  })

  const deepFlatten = flatten(false)
  deepFlatten(fromJS([1, 2, [3, 4, [5, [6]]]])) //[1, 2, 3, 4, 5, 6])

get

  const user = fromJS({
    id: 1,
    address: {
      street: 'Simborgargatan 12',
    },
  })
  const getAddress = get(['address'])
  getAddress(user) // Map {street: 'Simborgargatan 12'}

keySeq

  keySeq(fromJS({a: 'foo', b: 'bar', c: 'baz'})).toJS() //['a', 'b', 'c']

map

  const add5 = map((a) => a + 5)
  add5(fromJS([1, 2, 3])) // List [6, 7, 8]

reduce

  const sum = reduce((a, b) => a + b, 0)
  sum(fromJS([1, 2, 3, 4, 5, 6])) // 21

reverse

  reverse(fromJS([1, 2, 3, 4, 5])).toJS() //[5, 4, 3, 2, 1]

set

const user = fromJS({
  id: 1,
  address: {
    street: 'Simborgargatan 12',
  },
})
  const setStreet = set(['address', 'street']) // Map user

skip

  const skip3 = skip(3)
  skip3(fromJS([1, 2, 3, 4, 5])).toJS() // [4, 5]

skipLast

  const skipLast3 = skipLast(3)
  skipLast3(fromJS([1, 2, 3, 4, 5])).toJS() // [1, 2]

some

  const someEven = some(isEven)
  someEven(fromJS([1, 4, 3])) // true

sort

  const sortHighest = sort((a, b) => b - a)
  sortHighest(fromJS([100, 20, 3, 44, 5])).toJS() // [100, 44, 20, 5, 3]

take

const take3 = take(3)
take3(fromJS([1, 2, 3, 4, 5])).toJS() // [1, 2, 3]

takeLast

  const takeLast3 = takeLast(3)
  takeLast3(fromJS([1, 2, 3, 4, 5])).toJS() // [3, 4, 5]

valueSeq

  valueSeq(fromJS({a: 'foo', b: 'bar', c: 'baz'})).toJS() // ['foo', 'bar', 'baz']