sync

js/src/id/id.ts

@@ -1,5 +1,5 @@
-import { ulid } from "ulid";
 import { z } from "zod";
+import { randomBytes } from "crypto";
 
 export namespace Identifier {
   const prefixes = {
@@ -7,18 +7,44 @@ export namespace Identifier {
     message: "msg",
   } as const;
 
-  export function create(
+  export function schema(prefix: keyof typeof prefixes) {
+    return z.string().startsWith(prefixes[prefix]);
+  }
+
+  const LENGTH = 24;
+
+  export function ascending(prefix: keyof typeof prefixes, given?: string) {
+    return generateID(prefix, false, given);
+  }
+
+  export function descending(prefix: keyof typeof prefixes, given?: string) {
+    return generateID(prefix, true, given);
+  }
+
+  function generateID(
     prefix: keyof typeof prefixes,
+    descending: boolean,
     given?: string,
   ): string {
     if (given) {
       if (given.startsWith(prefixes[prefix])) return given;
       throw new Error(`ID ${given} does not start with ${prefixes[prefix]}`);
     }
-    return [prefixes[prefix], ulid()].join("_");
-  }
 
-  export function schema(prefix: keyof typeof prefixes) {
-    return z.string().startsWith(prefixes[prefix]);
+    let now = BigInt(Date.now());
+
+    if (descending) {
+      now = ~now;
+    }
+
+    const timeBytes = Buffer.alloc(6);
+    for (let i = 0; i < 6; i++) {
+      timeBytes[i] = Number((now >> BigInt(40 - 8 * i)) & BigInt(0xff));
+    }
+
+    const randLength = (LENGTH - 12) / 2;
+    const random = randomBytes(randLength);
+
+    return prefix + "_" + timeBytes.toString("hex") + random.toString("hex");
   }
 }