Last change
on this file since 6c1585f was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago |
initial commit
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Property mode
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100644
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File size:
938 bytes
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[6a3a178] | 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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