In an interview, I was asked to hit the jsonplaceholder /posts and /comments endpoints and write a function that returns matched comments with posts where comment.postId == post.id then make a whole JSON object containing the post within the comments belongs to it.
I have been trying to implement it in a functional approach but cannot find a way of dealing with 2 arrays (2 inputs) as pipelines, compositions, transducers all accept unary functions.
I Even thought of having two pipelines one for processing the comments and the other for posts and joining their workflows at the end but couldn't implement it.
All I could come up with is mapping the comments themselves to be an array of objects where it has postId as a number that represents each post and comments as array of strings
import axios from 'axios'
import _ from 'ramda'
const { data: comments } = await axios.get(
'http://jsonplaceholder.typicode.com/comments',
)
const cIds = (comments) =>
_.pipe(
_.groupBy(_.prop('postId')),
_.map(_.pluck('body')),
_.map(_.flatten),
_.map(_.uniq),
_.toPairs,
_.map(_.zipObj(['postId', 'comments'])),
)(comments)
console.log(cIds(comments))
So anyone has an idea of how to do so in a functional manner?
I think I'm missing something in the question. This sounds like a fairly simple function. I might write it something like this:
const consolidate = ([posts, comments]) =>
posts .map (p => ({
...p,
comments: comments .filter (c => c.postId == p.id)
}))
const fullPosts = (postUrl, commentUrl) =>
Promise .all ([axios .get (postUrl), axios .get (commentUrl)])
.then (consolidate)
fullPosts (
'https://jsonplaceholder.typicode.com/posts',
'https://jsonplaceholder.typicode.com/comments'
) .then (console .log, console .warn).as-console-wrapper {max-height: 100% !important; top: 0}<script>const axios = {get: (url) => fetch (url) .then (r => r .json ())} // dummy axios</script>I'm one of the founders of Ramda, and a big fan, but I don't know that it offers much here.