Discussion on: Public Solving: Generating secure password

const optionValues = {
  lowercase: 'abcdefghijklmnopqrstuvwxyz',
  uppercase: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
  numbers: '0123456789',
  specialCharacters: '!@#$%^&*()'
}

export const generatePassword = (length, options) => {
  const selectedOptionsCount =
    Object.values(options).filter(Boolean).length
  if (length < selectedOptionsCount) {
      throw new Error(
        'length is too short to include selected options'
      )
  } else if (selectedOptionsCount === 0) {
      throw new Error('please select at least one option')
  }
  const rand = new Uint16Array(length)
  crypto.getRandomValues(rand)
  const optionKeys = Object.keys(options)
    .filter((key) => options[key])
  return [...new Array(length)]
    .map((_, i) => {
      // make sure to include at least one of each selected option
      // and randomize the rest
      const currentOption = i < selectedOptionsCount
        ? optionValues[optionKeys[i]]
        : optionValues[optionKeys[rand[i] % optionKeys.length]]
      return currentOption[(rand[i] >> 2) % currentOption.length]
    })
    // shuffle for extra randomness
    .sort(() => 0.5 - Math.random())
    .join('')
}