Medicare number generator

generate-medicare-card-numbers.ts

const fs = require('fs')

// Grabbed from here: https://gist.github.com/Ugrend/09890dbc7a049651d470d1f8b6b73e1a
function randomMedicareNumber(): string {
  let sum = Math.floor(Math.random() * 5) + 2
  const weights = [1, 3, 7, 9, 1, 3, 7, 9]
  const num = [sum]
  for (let i = 0; i < 7; i++) {
    const n = Math.floor(Math.random() * 10)
    sum += n * weights[i + 1]
    num.push(n)
  }
  num.push(sum % 10)
  return num.join('') + '1/1'
}

/**
 * Generates many medicare card numbers. Used for development purposes only.
 * Writes to file: medicare-numbers.json
 * @param amount
 */
function generateMany(amount = 1000 as number): void {
  const seed = new Array(amount).fill(undefined)

  const many = seed.map(() => {
    const r = randomMedicareNumber()
    return r
  })

  console.log(JSON.stringify(many))

  fs.writeFileSync('medicare-numbers.json', JSON.stringify(many))
}

generateMany()

/** Usage: npx node-ts --inspect generate-medicare-card-number.ts */