From 857b393eb49479ee3cc2f7a438fc79c2ef04c3bd Mon Sep 17 00:00:00 2001
From: willclarktech <willclarktech@users.noreply.github.com>
Date: Tue, 11 May 2021 12:28:59 +0200
Subject: [PATCH] proto-signing: Add makeCosmoshubPath helper

---
 packages/proto-signing/src/index.ts      |  1 +
 packages/proto-signing/src/paths.spec.ts | 26 ++++++++++++++++++++++++
 packages/proto-signing/src/paths.ts      | 15 ++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 packages/proto-signing/src/paths.spec.ts
 create mode 100644 packages/proto-signing/src/paths.ts

diff --git a/packages/proto-signing/src/index.ts b/packages/proto-signing/src/index.ts
index e6490c7d..3136762c 100644
--- a/packages/proto-signing/src/index.ts
+++ b/packages/proto-signing/src/index.ts
@@ -16,6 +16,7 @@ export {
 } from "./registry";
 export { DirectSecp256k1HdWallet, DirectSecp256k1HdWalletOptions } from "./directsecp256k1hdwallet";
 export { DirectSecp256k1Wallet } from "./directsecp256k1wallet";
+export { makeCosmoshubPath } from "./paths";
 export { decodePubkey, encodePubkey } from "./pubkey";
 export {
   AccountData,
diff --git a/packages/proto-signing/src/paths.spec.ts b/packages/proto-signing/src/paths.spec.ts
new file mode 100644
index 00000000..17fd85b6
--- /dev/null
+++ b/packages/proto-signing/src/paths.spec.ts
@@ -0,0 +1,26 @@
+import { Slip10RawIndex } from "@cosmjs/crypto";
+
+import { makeCosmoshubPath } from "./paths";
+
+describe("paths", () => {
+  describe("makeCosmoshubPath", () => {
+    it("works", () => {
+      // m/44'/118'/0'/0/0
+      expect(makeCosmoshubPath(0)).toEqual([
+        Slip10RawIndex.hardened(44),
+        Slip10RawIndex.hardened(118),
+        Slip10RawIndex.hardened(0),
+        Slip10RawIndex.normal(0),
+        Slip10RawIndex.normal(0),
+      ]);
+      // m/44'/118'/0'/0/123
+      expect(makeCosmoshubPath(123)).toEqual([
+        Slip10RawIndex.hardened(44),
+        Slip10RawIndex.hardened(118),
+        Slip10RawIndex.hardened(0),
+        Slip10RawIndex.normal(0),
+        Slip10RawIndex.normal(123),
+      ]);
+    });
+  });
+});
diff --git a/packages/proto-signing/src/paths.ts b/packages/proto-signing/src/paths.ts
new file mode 100644
index 00000000..bf4dd185
--- /dev/null
+++ b/packages/proto-signing/src/paths.ts
@@ -0,0 +1,15 @@
+import { HdPath, Slip10RawIndex } from "@cosmjs/crypto";
+
+/**
+ * The Cosmos Hub derivation path in the form `m/44'/118'/0'/0/a`
+ * with 0-based account index `a`.
+ */
+export function makeCosmoshubPath(a: number): HdPath {
+  return [
+    Slip10RawIndex.hardened(44),
+    Slip10RawIndex.hardened(118),
+    Slip10RawIndex.hardened(0),
+    Slip10RawIndex.normal(0),
+    Slip10RawIndex.normal(a),
+  ];
+}