tinyhttp / malibu / 6760091955

import { randomBytes, createHash, createHmac, timingSafeEqual } from 'crypto'

/**

 * Generate a secure type safe UID with specified length.

 * Rewrite of https://github.com/crypto-utils/uid-safe

 * @param {Number} length UID length

 * @returns {String} Type safe UID

 */

export function typeSafeUID(length: number): string {

  return randomBytes(length).toString('base64').replace(/=+$/, '').replace(/\+/g, '-').replace(/\//g, '_')

}

/**

 * Generate a (not secure) quick salt with specified length.

 * Rewrite of https://github.com/crypto-utils/rndm

 * @param {Number} length Salt length

 * @returns {String} Salt

 */

export function randomBase62(length: number): string {

  const availableCharacters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'

  const byteLength = Buffer.byteLength(availableCharacters)

  let salt = ''

  for (let i = 0; i < length; i++) {

    salt += availableCharacters[Math.floor(byteLength * Math.random())]

  }

  return salt

}

/**

 * Create a SHA1 hash from specified string

 * Rewrite of a function from https://github.com/pillarjs/csrf

 * @param {String} str Dirty string

 * @returns {String} Hashed string

 */

export function hash(str: string): string {

  return createHash('sha256')

    .update(str, 'ascii')

    .digest('base64')

    .replace(/=+$/, '')

    .replace(/\+/g, '-')

    .replace(/\//g, '_')

}

/**

 * Compare two keys, to check if they have the same creation duration.

 * Rewrite of https://github.com/suryagh/tsscmp

 * @param {String} a Key #1

 * @param {String} b Key #2

 * @returns {Boolean} Whether both keys matches or not

 */

export function timeSafeCompare(a: string, b: string): boolean {

  const key = randomBytes(32)

  const aHMAC = createHmac('sha256', key).update(String(a)).digest()

  const bHMAC = createHmac('sha256', key).update(String(b)).digest()

  return timingSafeEqual(aHMAC, bHMAC)

}