48 lines
1.4 KiB
JavaScript
48 lines
1.4 KiB
JavaScript
/* @ts-self-types="./index.d.ts" */
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import { urlAlphabet as scopedUrlAlphabet } from './url-alphabet/index.js'
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export { urlAlphabet } from './url-alphabet/index.js'
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export let random = bytes => crypto.getRandomValues(new Uint8Array(bytes))
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export let customRandom = (alphabet, defaultSize, getRandom) => {
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let safeByteCutoff = 256 - (256 % alphabet.length)
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if (safeByteCutoff === 256) {
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let mask = alphabet.length - 1
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return (size = defaultSize) => {
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if (!size) return ''
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let id = ''
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while (true) {
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let bytes = getRandom(size)
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let j = size
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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 step = Math.ceil((1.6 * 256 * defaultSize) / safeByteCutoff)
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return (size = defaultSize) => {
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if (!size) return ''
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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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if (bytes[j] < safeByteCutoff) {
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id += alphabet[bytes[j] % alphabet.length]
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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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}
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export let customAlphabet = (alphabet, size = 21) =>
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customRandom(alphabet, size | 0, random)
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export let nanoid = (size = 21) => {
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let id = ''
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let bytes = crypto.getRandomValues(new Uint8Array((size |= 0)))
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while (size--) {
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id += scopedUrlAlphabet[bytes[size] & 63]
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}
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return id
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}
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