[Ramda] Filter, Reject and Partition

Posted 2020-08-09 Answer1215

We‘ll learn how to get a subset of an array by specifying items to include with filter, or items to exclude using reject. We‘ll also look at how to get the results from both filter and reject, neatly separated with partition.

 

// we don‘t need to require in Plunker!
//const R = require(‘ramda‘)

const pets = [
  {name: ‘Spike‘, type: ‘dog‘},
  {name: ‘Mittens‘, type: ‘cat‘},
  {name: ‘Rover‘, type: ‘dog‘},
  {name: ‘Fluffy‘, type: ‘cat‘},
  {name: ‘Fido‘, type: ‘dog‘}
]

const dogCheck = pet => pet.type == ‘dog‘

// const result = R.filter(dogCheck, pets)
// const result = R.reject(dogCheck, pets)

const result = R.partition(dogCheck, pets)

console.log(result)
document.getElementById(‘output‘).innerhtml = `${JSON.stringify(result)}`

 

/*
[
[{"name":"Spike","type":"dog"},{"name":"Rover","type":"dog"},
{"name":"Fido","type":"dog"}],

[{"name":"Mittens","type":"cat"},{"name":"Fluffy","type":"cat"}]
]
*/