| import crypto from 'crypto' |
| import { urlAlphabet } from './url-alphabet/index.js' |
| const POOL_SIZE_MULTIPLIER = 128 |
| let pool, poolOffset |
| let fillPool = bytes => { |
| if (!pool || pool.length < bytes) { |
| pool = Buffer.allocUnsafe(bytes * POOL_SIZE_MULTIPLIER) |
| crypto.randomFillSync(pool) |
| poolOffset = 0 |
| } else if (poolOffset + bytes > pool.length) { |
| crypto.randomFillSync(pool) |
| poolOffset = 0 |
| } |
| poolOffset += bytes |
| } |
| let random = bytes => { |
| fillPool((bytes -= 0)) |
| return pool.subarray(poolOffset - bytes, poolOffset) |
| } |
| let customRandom = (alphabet, size, getRandom) => { |
| let mask = (2 << (31 - Math.clz32((alphabet.length - 1) | 1))) - 1 |
| let step = Math.ceil((1.6 * mask * size) / alphabet.length) |
| return () => { |
| let id = '' |
| while (true) { |
| let bytes = getRandom(step) |
| let i = step |
| while (i--) { |
| id += alphabet[bytes[i] & mask] || '' |
| if (id.length === size) return id |
| } |
| } |
| } |
| } |
| let customAlphabet = (alphabet, size) => customRandom(alphabet, size, random) |
| let nanoid = (size = 21) => { |
| fillPool((size -= 0)) |
| let id = '' |
| for (let i = poolOffset - size; i < poolOffset; i++) { |
| id += urlAlphabet[pool[i] & 63] |
| } |
| return id |
| } |
| export { nanoid, customAlphabet, customRandom, urlAlphabet, random } |