initial commit

src/lib/slug.ts

@@ -0,0 +1,39 @@
+import Sqids from "sqids";
+
+export type Slug = string & { readonly __tag: unique symbol };
+
+export class Slugs {
+  private static instance: Slugs;
+  private sqids!: Sqids;
+
+  private constructor() {
+    if (Slugs.instance) return Slugs.instance;
+    Slugs.instance = this;
+
+    this.sqids = new Sqids({
+      alphabet: "dbnixSPYJNy5hvsqCWIHwEKTFutV6r4Xa32okL8RQUj7Am9DcpgfZezMBG",
+    });
+  }
+
+  static encode(num: number | bigint): Slug {
+    const sqids = new Slugs().sqids;
+    const thirtyTwoBitMax = BigInt(0xffffffff);
+    if (typeof num === "bigint" && num > thirtyTwoBitMax) {
+      const arr = [];
+      while (num > 0) {
+        arr.push(Number(num & thirtyTwoBitMax));
+        num >>= 32n;
+      }
+      return sqids.encode(arr) as Slug;
+    } else {
+      return sqids.encode([Number(num)]) as Slug;
+    }
+  }
+
+  static decode(slug: Slug): number | bigint {
+    const ns = new Slugs().sqids.decode(slug);
+    if (ns.length === 1) return ns[0];
+
+    return ns.reduceRight((big, each) => (big << 32n) + BigInt(each), 0n);
+  }
+}