CODEWITHSUNDEEP
javascriptarraysfunctional-programmingramda.js
cpoliver
cpoliver

Reputation: 65

How to get two arrays by mapping a predicate over an input array with Ramda

Is there a concise way to achieve the same result as the below but:

I thought about using reduce to update an accumulator object containing the passed/failed arrays, but I'm not sure if there was a smarter/less verbose option

const predicate = i => i % 2 === 0;
const predicatePassed = [];
const predicateFailed = [];

[1, 2, 3, 4].forEach(i => predicate(i) ? predicatePassed.push(i) : predicateFailed.push(i))

// predicatePassed === [2, 4]
// predicateFailed === [1, 3]

Upvotes: 2

Views: 286

Answers (1)

Ori Drori
Ori Drori

Reputation: 191986

You can use R.partition:

const predicate = i => i % 2 === 0;

const [predicatePassed, predicateFailed] = R.partition(predicate)([1, 2, 3, 4]);

console.log(predicatePassed);
console.log(predicateFailed);
<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>

Upvotes: 7

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