Create normalizeBech32

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to
 
 ## [Unreleased]
 
+### Added
+
+- @cosmjs/encoding: Create `normalizeBech32`.
+
 ## [0.28.1] - 2022-03-30
 
 ### Added

packages/encoding/src/bech32.spec.ts

@@ -1,4 +1,4 @@
-import { fromBech32, toBech32 } from "./bech32";
+import { fromBech32, normalizeBech32, toBech32 } from "./bech32";
 import { fromHex } from "./hex";
 
 describe("bech32", () => {
@@ -89,4 +89,24 @@ describe("bech32", () => {
       expect(() => fromBech32("eth1n48g2mjh9Ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
     });
   });
+
+  describe("normalizeBech32", () => {
+    it("works", () => {
+      expect(normalizeBech32("eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toEqual(
+        "eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw",
+      );
+      expect(normalizeBech32("ETH1N48G2MJH9EZZ7ZJTYA37WTGG5R5EMR0DRKWLGW")).toEqual(
+        "eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw",
+      );
+    });
+
+    it("throws for mixed case addresses", () => {
+      // "Decoders MUST NOT accept strings where some characters are uppercase and some are lowercase (such strings are referred to as mixed case strings)."
+      // https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
+      expect(() => normalizeBech32("Eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => normalizeBech32("eTh1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => normalizeBech32("ETH1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => normalizeBech32("eth1n48g2mjh9Ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+    });
+  });
 });

packages/encoding/src/bech32.ts

@@ -16,6 +16,17 @@ export function fromBech32(
   };
 }
 
+/**
+ * Takes a bech32 address and returns a normalized (i.e. lower case) representation of it.
+ *
+ * The input is validated along the way, which makes this significantly safer than
+ * using `address.toLowerCase()`.
+ */
+export function normalizeBech32(address: string): string {
+  const { prefix, data } = fromBech32(address);
+  return toBech32(prefix, data);
+}
+
 /**
  * @deprecated This class is deprecated and will be removed soon. Please use fromBech32() and toBech32() instead. For more details please refer to https://github.com/cosmos/cosmjs/issues/1053.
  */