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- import crypto from 'crypto'
- import { urlAlphabet } from '../url-alphabet/index.js'
- let random = bytes =>
- new Promise((resolve, reject) => {
- crypto.randomFill(Buffer.allocUnsafe(bytes), (err, buf) => {
- if (err) {
- reject(err)
- } else {
- resolve(buf)
- }
- })
- })
- let customAlphabet = (alphabet, defaultSize = 21) => {
- let mask = (2 << (31 - Math.clz32((alphabet.length - 1) | 1))) - 1
- let step = Math.ceil((1.6 * mask * defaultSize) / alphabet.length)
- let tick = (id, size = defaultSize) =>
- random(step).then(bytes => {
- let i = step
- while (i--) {
- id += alphabet[bytes[i] & mask] || ''
- if (id.length === size) return id
- }
- return tick(id, size)
- })
- return size => tick('', size)
- }
- let nanoid = (size = 21) =>
- random(size).then(bytes => {
- let id = ''
- while (size--) {
- id += urlAlphabet[bytes[size] & 63]
- }
- return id
- })
- export { nanoid, customAlphabet, random }
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