nostr package part 1

packages/nostr/src/legacy/Links.ts

@@ -0,0 +1,59 @@
+import * as secp from "@noble/secp256k1";
+import { bech32 } from "bech32";
+
+export enum NostrPrefix {
+  PublicKey = "npub",
+  PrivateKey = "nsec",
+  Note = "note",
+
+  // TLV prefixes
+  Profile = "nprofile",
+  Event = "nevent",
+  Relay = "nrelay",
+}
+
+export interface TLVEntry {
+  type: number;
+  length: number;
+  value: string; // hex encoded data
+}
+
+export function encodeTLV(hex: string, prefix: NostrPrefix, relays?: string[]) {
+  if (typeof hex !== "string" || hex.length === 0 || hex.length % 2 !== 0) {
+    return "";
+  }
+
+  const enc = new TextEncoder();
+  const buf = secp.utils.hexToBytes(hex);
+
+  const tl0 = [0, buf.length, ...buf];
+  const tl1 =
+    relays
+      ?.map((a) => {
+        const data = enc.encode(a);
+        return [1, data.length, ...data];
+      })
+      .flat() ?? [];
+
+  return bech32.encode(prefix, bech32.toWords([...tl0, ...tl1]));
+}
+
+export function decodeTLV(str: string) {
+  const decoded = bech32.decode(str);
+  const data = bech32.fromWords(decoded.words);
+
+  const entries: TLVEntry[] = [];
+  let x = 0;
+  while (x < data.length) {
+    const t = data[x];
+    const l = data[x + 1];
+    const v = data.slice(x + 2, x + 2 + l);
+    entries.push({
+      type: t,
+      length: l,
+      value: secp.utils.bytesToHex(new Uint8Array(v)),
+    });
+    x += 2 + l;
+  }
+  return entries;
+}