Last change
on this file since 76712b2 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago |
initial commit
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Property mode
set to
100644
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File size:
938 bytes
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1 | let crypto = require('crypto')
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2 | let { urlAlphabet } = require('../url-alphabet/index.cjs')
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3 | let random = bytes =>
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4 | new Promise((resolve, reject) => {
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5 | crypto.randomFill(Buffer.allocUnsafe(bytes), (err, buf) => {
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6 | if (err) {
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7 | reject(err)
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8 | } else {
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9 | resolve(buf)
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10 | }
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11 | })
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12 | })
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13 | let customAlphabet = (alphabet, size) => {
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14 | let mask = (2 << (31 - Math.clz32((alphabet.length - 1) | 1))) - 1
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15 | let step = Math.ceil((1.6 * mask * size) / alphabet.length)
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16 | let tick = id =>
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17 | random(step).then(bytes => {
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18 | let i = step
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19 | while (i--) {
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20 | id += alphabet[bytes[i] & mask] || ''
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21 | if (id.length === size) return id
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22 | }
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23 | return tick(id)
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24 | })
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25 | return () => tick('')
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26 | }
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27 | let nanoid = (size = 21) =>
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28 | random(size).then(bytes => {
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29 | let id = ''
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30 | while (size--) {
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31 | id += urlAlphabet[bytes[size] & 63]
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32 | }
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33 | return id
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34 | })
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35 | module.exports = { nanoid, customAlphabet, random }
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