38 lines
1.1 KiB
TypeScript
38 lines
1.1 KiB
TypeScript
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/**
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* RFC4122 v4 UUID that also works in a NON-secure context (plain `http://` on a LAN
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* IP, e.g. when localhost is unavailable), where `crypto.randomUUID` is undefined.
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*
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* Order of preference: crypto.randomUUID (secure contexts) → crypto.getRandomValues
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* (available over http too) → Math.random fallback.
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*/
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export function uuid(): string {
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const c: Crypto | undefined =
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typeof globalThis !== "undefined" ? (globalThis.crypto as Crypto | undefined) : undefined;
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if (c && typeof c.randomUUID === "function") {
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return c.randomUUID();
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}
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const bytes = new Uint8Array(16);
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if (c && typeof c.getRandomValues === "function") {
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c.getRandomValues(bytes);
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} else {
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for (let i = 0; i < 16; i++) bytes[i] = Math.floor(Math.random() * 256);
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}
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bytes[6] = (bytes[6] & 0x0f) | 0x40; // version 4
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bytes[8] = (bytes[8] & 0x3f) | 0x80; // RFC4122 variant
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const hex = Array.from(bytes, (b) => b.toString(16).padStart(2, "0"));
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return (
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hex.slice(0, 4).join("") +
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"-" +
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hex.slice(4, 6).join("") +
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"-" +
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hex.slice(6, 8).join("") +
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"-" +
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hex.slice(8, 10).join("") +
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"-" +
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hex.slice(10, 16).join("")
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);
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}
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