Add decodeCosmosSdkDecFromProto

CHANGELOG.md

@@ -14,6 +14,8 @@ and this project adheres to
   ([#932]).
 - @cosmjs/stargate: Merge `DeliverTxFailure` and `DeliverTxSuccess` into a
   single `DeliverTxResponse` ([#878], [#949]). Add `assertIsDeliverTxFailure`.
+- @cosmjs/stargate: Created `types.Dec` decoder function
+  `decodeCosmosSdkDecFromProto`.
 - @cosmjs/amino: Added `StdTx`, `isStdTx` and `makeStdTx` and removed them from
   @cosmjs/launchpad. They are re-exported in @cosmjs/launchpad for backwards
   compatibility.

packages/stargate/src/index.ts

@@ -62,6 +62,7 @@ export {
   BankExtension,
   createPagination,
   createProtobufRpcClient,
+  decodeCosmosSdkDecFromProto,
   DistributionExtension,
   GovExtension,
   GovParamsType,

packages/stargate/src/queries/index.ts

@@ -11,4 +11,9 @@ export { GovExtension, GovParamsType, GovProposalId, setupGovExtension } from ".
 export { IbcExtension, setupIbcExtension } from "./ibc";
 export { setupStakingExtension, StakingExtension } from "./staking";
 export { setupTxExtension, TxExtension } from "./tx";
-export { createPagination, createProtobufRpcClient, ProtobufRpcClient } from "./utils";
+export {
+  createPagination,
+  createProtobufRpcClient,
+  decodeCosmosSdkDecFromProto,
+  ProtobufRpcClient,
+} from "./utils";

packages/stargate/src/queries/utils.spec.ts

@@ -0,0 +1,21 @@
+import { fromHex } from "@cosmjs/encoding";
+
+import { decodeCosmosSdkDecFromProto } from "./utils";
+
+describe("utils", () => {
+  describe("decodeCosmosSdkDecFromProto", () => {
+    it("works for string inputs", () => {
+      expect(decodeCosmosSdkDecFromProto("0").toString()).toEqual("0");
+      expect(decodeCosmosSdkDecFromProto("1").toString()).toEqual("0.000000000000000001");
+      expect(decodeCosmosSdkDecFromProto("3000000").toString()).toEqual("0.000000000003");
+      expect(decodeCosmosSdkDecFromProto("123456789123456789").toString()).toEqual("0.123456789123456789");
+      expect(decodeCosmosSdkDecFromProto("1234567891234567890").toString()).toEqual("1.23456789123456789");
+    });
+
+    it("works for byte inputs", () => {
+      expect(decodeCosmosSdkDecFromProto(fromHex("313330303033343138373830313631333938")).toString()).toEqual(
+        "0.130003418780161398",
+      );
+    });
+  });
+});

packages/stargate/src/queries/utils.ts

@@ -1,5 +1,5 @@
-import { Bech32 } from "@cosmjs/encoding";
-import { Uint64 } from "@cosmjs/math";
+import { Bech32, fromAscii } from "@cosmjs/encoding";
+import { Decimal, Uint64 } from "@cosmjs/math";
 import { PageRequest } from "cosmjs-types/cosmos/base/query/v1beta1/pagination";
 import Long from "long";
 
@@ -53,3 +53,14 @@ export function longify(value: string | number | Long | Uint64): Long {
   const checkedValue = Uint64.fromString(value.toString());
   return Long.fromBytesBE([...checkedValue.toBytesBigEndian()], true);
 }
+
+/**
+ * Takes a string or binary encoded `github.com/cosmos/cosmos-sdk/types.Dec` from the
+ * protobuf API and converts it into a `Decimal` with 18 fractional digits.
+ *
+ * See https://github.com/cosmos/cosmos-sdk/issues/10863 for more context why this is needed.
+ */
+export function decodeCosmosSdkDecFromProto(input: string | Uint8Array): Decimal {
+  const asString = typeof input === "string" ? input : fromAscii(input);
+  return Decimal.fromAtomics(asString, 18);
+}