backend.js

// eslint-disable-next-line no-undef
const { v4 } = require('uuid')

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

const asc = arr => arr.sort((a, b) => a - b);

const sum = arr => arr.reduce((a, b) => a + b, 0);

const mean = arr => sum(arr) / arr.length;

const quantile = (arr, q) => {
  const sorted = asc(arr);
  const pos = (sorted.length - 1) * q;
  const base = Math.floor(pos);
  const rest = pos - base;
  if (sorted[base + 1] !== undefined) {
      return sorted[base] + rest * (sorted[base + 1] - sorted[base]);
  } else {
      return sorted[base];
  }
};

// eslint-disable-next-line no-undef
module.exports = () => {
  const data = { checks: [], check_stats: [] }
  console.log("please wait while I create a ton of random data..")
  for (let i = 0; i < 20; i++) {
    const id = v4()
    const type = getRandomInt(2) === 1 ? 'API' : 'BROWSER'
    const checkStats = []
    let bucketValues = []
    const hourlyBuckets = []
    const startingDate = new Date()
    let firstHour = startingDate.getHours()
    for (let j = 0; j < 30000; j++) {
        const timestamp = startingDate - (j * 30000)
        const responseTime = getRandomInt(1000)
        const result = { checkId: id, success: getRandomInt(2), timestamp, responseTime }
        checkStats.push(result)
        bucketValues.push(result)
        const currentHour = new Date(timestamp)
        if (currentHour.getHours()!==firstHour){
            firstHour = currentHour.getHours()
            currentHour.setHours(firstHour,0,0,0)
            const bucket = {
                checkId: id,
                success: mean(bucketValues.map(checkStat => checkStat.success)),
                avg: mean(checkStats.map(checkStat => checkStat.responseTime)),
                p95: quantile(checkStats.map(checkStat => checkStat.responseTime), .95),
                p99: quantile(checkStats.map(checkStat => checkStat.responseTime), .99),
                timestamp: currentHour.getTime()
            }
            bucketValues = []
            hourlyBuckets.push(bucket)
        }
    }
    const check = { id, name: `Check ${i}`, type}
    check.success = mean(checkStats.map(checkStat => checkStat.success))
    check.avg = mean(checkStats.map(checkStat => checkStat.responseTime))
    check.p95 = quantile(checkStats.map(checkStat => checkStat.responseTime), .95)
    check.p99 = quantile(checkStats.map(checkStat => checkStat.responseTime), .99)
    data.checks.push(check)
    data.check_stats.push(...hourlyBuckets)
  }
  console.log("thanks :-)")
  return data
}