Clément Fiere
52 lines
2.1 KiB
TypeScript
52 lines
2.1 KiB
TypeScript
let uuidFallbackCounter = 0;
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let uuidFallbackContextCounter = 0;
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function createUuidFallbackContext(): string {
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const entropy = new Uint32Array(2);
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if (typeof crypto !== "undefined" && crypto.getRandomValues) {
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try {
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crypto.getRandomValues(entropy);
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return entropy[0].toString(16).padStart(8, "0");
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} catch {
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// Fall through to the non-cryptographic legacy-environment fallback.
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}
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}
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const monotonic = typeof performance !== "undefined" ? Math.floor(performance.now() * 1000) : 0;
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const counter = uuidFallbackContextCounter++;
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return ((Date.now() ^ monotonic ^ counter) >>> 0).toString(16).padStart(8, "0");
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}
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// Keep a per-module component so two tabs generating IDs in the same
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// millisecond do not share the timestamp/counter prefix. Prefer Web Crypto
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// entropy when available; old environments get a monotonic best-effort ID.
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const uuidFallbackContext = createUuidFallbackContext();
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/**
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* Generate a UUID. Falls back to crypto.getRandomValues when randomUUID is
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* unavailable (e.g., HTTP on non-localhost), then to a UUID-shaped fallback
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* with a per-context component for legacy environments without any Web Crypto API.
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*/
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export function generateUUID(): string {
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if (typeof crypto !== "undefined" && crypto.randomUUID) {
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return crypto.randomUUID();
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}
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if (typeof crypto !== "undefined" && crypto.getRandomValues) {
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const bytes = crypto.getRandomValues(new Uint8Array(16));
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bytes[6] = (bytes[6] & 0x0f) | 0x40;
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bytes[8] = (bytes[8] & 0x3f) | 0x80;
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const hex = Array.from(bytes, (byte) => byte.toString(16).padStart(2, "0")).join("");
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return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
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}
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const context = uuidFallbackContext;
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const timestamp = Date.now().toString(16).padStart(12, "0").slice(-12);
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const counter = (uuidFallbackCounter++ >>> 0).toString(16).padStart(8, "0");
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const chars = `${context}${timestamp}${counter}`.padEnd(32, "0").slice(0, 32).split("");
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chars[12] = "4";
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chars[16] = "8";
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const hex = chars.join("");
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return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
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}
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