Fork of https://gist.github.com/mykeels/8396f87d42a809697d08f6b6c9cd8db0 using child-process via https://github.com/rvagg/node-worker-farm

index.js

const express = require('express')
const os = require('os')
const app = express()
const workerFarm = require('worker-farm')
const worker = workerFarm(require.resolve('./worker.js'))

app.get('/', (req, res) => {
    const max = Number(req.query.max) || 1000
    worker(max, (err, primes) => {
        if (err) res.status(500).send(err)
        else res.json(primes)
    })
})

app.listen(process.env.PORT || 3030)

console.log('app is running!')

module.exports = app

worker.js

const isPrime = require('./is-prime')

module.exports = function (max = 0, callback = (err, result) => ({})) {
    try {
        const primes = []

        for (let i = 1; i <= max; i++) {
            if (isPrime(i)) primes.push(i)
        }
        
        callback(null, primes)
    }
    catch (ex) {
        callback(ex)
        console.error(ex)
    }
}