Dump and read lots of JSONs in node

dump_and_read_jsons.js

const fs = require('fs')

o = {
  ACCTOUNT_NUMBER: '1234567890',
  CUSTOMER_NAME: 'ACME Products and Services, Inc.',
  ADDRESS: '123 Main Street',
  CITY: 'Albuquerque',
  STATE: 'NM',
  ZIP: '87101-1234'
}

const fileContents = []
for (let i=0; i<200; ++i) fileContents.push(o)

const files = []
for (let i=0; i<3000; ++i) {
  files.push(`/tmp/a_${i}`)
}

const timeIt = async f => {
  const startTime = new Date()
  await f()
  console.log(`elapsed time: ${(new Date() - startTime)/1000}s`)
}

const main = async () => {
  console.log(`dumping and writing ${files.length} JSONs of size ${Math.round(JSON.stringify(fileContents).length/1024)}KB each`)

  await timeIt(() => Promise.all(files.map(file => (() => 
    fs.promises.writeFile(file, JSON.stringify(fileContents))
  )())))

  console.log(`reading all the files`)
  await timeIt(() => Promise.all(files.map(file => (async () => {
    JSON.parse(await fs.promises.readFile(file))
  })())))
}

main().catch(err => {
  console.error(err)
  process.exit(2)
})