Partition in Node v12

index.js

const R = require('ramda')
const _ = require('lodash')

const NS_PER_SEC = 1e9
const NS_PER_MILLIS = 1e6

function partitionV2(cond, data) {
	const accepted = []
  	const rejected = []
    const len = data.length
    let elem
    let i = 0
    while(i < len) {
        elem = data[i]
        if (cond(elem)) {
            accepted.push(elem)
        } else {
            rejected.push(elem)
        }
        ++i
    }
  
  	return [accepted, rejected]
}

function singleRun(fn) {
    const startTime = process.hrtime()
    fn()
    const duration = process.hrtime(startTime)

    // result in nanos
    return duration[0] * NS_PER_SEC + duration[1]
}

const add = (a, b) => a + b

function run(fn, n) {
    const m = n
    const runs = []
    while (0 <-- n) {
        runs.push(singleRun(fn))
    }

    // result in millis
    return runs.reduce(add) / NS_PER_MILLIS
}

const isOdd = x => x % 2 !== 0

const runTests = (cond, size, times) => {
    const data = R.range(1, size + 1)

    const funcs = [
        ['Ramda', () => R.partition(cond, data)],
        ['Lodash', () => _.partition(data, cond)],
        ['Vanilla', () => partitionV2(cond, data)]
    ]

    console.log(`\nArray :: size ${size} :: times ${times}:\n`)

    funcs.forEach(([libName, func]) => {
        console.log(`-- ${libName}:\t${run(func, times)} millis`)
    })

    console.log('\n')
}

runTests(isOdd, 1000000, 100)
runTests(isOdd, 10000, 1000)
runTests(isOdd, 100, 10000)

package.json

{
  "name": "performance",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "lodash": "4.17.15",
    "ramda": "0.26.1"
  }
}

results.txt

Array :: size 1000000 :: times 100:

-- Ramda:	5604.457264 millis
-- Lodash:	2229.485391 millis
-- Vanilla:	2074.14233 millis



Array :: size 10000 :: times 1000:

-- Ramda:	462.500396 millis
-- Lodash:	111.673181 millis
-- Vanilla:	94.139585 millis



Array :: size 100 :: times 10000:

-- Ramda:	68.294782 millis
-- Lodash:	18.926197 millis
-- Vanilla:	9.33258 millis