blob: 397ec28327e2574237c94a302c3eb718f0c9a669 [file] [log] [blame]
let crypto = require('crypto')
let { urlAlphabet } = require('../url-alphabet/index.cjs')
let random = bytes =>
new Promise((resolve, reject) => {
crypto.randomFill(Buffer.allocUnsafe(bytes), (err, buf) => {
if (err) {
reject(err)
} else {
resolve(buf)
}
})
})
let customAlphabet = (alphabet, size) => {
let mask = (2 << (31 - Math.clz32((alphabet.length - 1) | 1))) - 1
let step = Math.ceil((1.6 * mask * size) / alphabet.length)
let tick = id =>
random(step).then(bytes => {
let i = step
while (i--) {
id += alphabet[bytes[i] & mask] || ''
if (id.length === size) return id
}
return tick(id)
})
return () => tick('')
}
let nanoid = (size = 21) =>
random(size).then(bytes => {
let id = ''
while (size--) {
id += urlAlphabet[bytes[size] & 63]
}
return id
})
module.exports = { nanoid, customAlphabet, random }