35 lines
1.0 KiB
JavaScript
35 lines
1.0 KiB
JavaScript
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let { urlAlphabet } = require('./url-alphabet/index.cjs')
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let random = bytes => crypto.getRandomValues(new Uint8Array(bytes))
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let customRandom = (alphabet, defaultSize, getRandom) => {
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let mask = (2 << (Math.log(alphabet.length - 1) / Math.LN2)) - 1
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let step = -~((1.6 * mask * defaultSize) / alphabet.length)
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return (size = defaultSize) => {
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let id = ''
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while (true) {
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let bytes = getRandom(step)
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let j = step
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while (j--) {
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id += alphabet[bytes[j] & mask] || ''
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if (id.length === size) return id
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}
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}
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}
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}
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let customAlphabet = (alphabet, size = 21) =>
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customRandom(alphabet, size, random)
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let nanoid = (size = 21) =>
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crypto.getRandomValues(new Uint8Array(size)).reduce((id, byte) => {
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byte &= 63
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if (byte < 36) {
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id += byte.toString(36)
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} else if (byte < 62) {
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id += (byte - 26).toString(36).toUpperCase()
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} else if (byte > 62) {
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id += '-'
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} else {
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id += '_'
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}
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return id
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}, '')
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module.exports = { nanoid, customAlphabet, customRandom, urlAlphabet, random }
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