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