From cf5ef706a852ae981e013c137d70d47b8e4d0d83 Mon Sep 17 00:00:00 2001
From: Matt <90358481+xbtmatt@users.noreply.github.com>
Date: Tue, 31 Oct 2023 00:55:49 -0700
Subject: [PATCH] [TypeTag] Adding explicit return types for TypeTag types, fix
 vectors `toString()` function, add aptosCoinStructTag (#144)

* Adding explicit string return values and other misc changes to typeTagParser.ts

* Formatting

* Fixing string format return value
---
 src/transactions/typeTag/index.ts | 20 +++++++++++++-------
 tests/unit/typeTagParser.test.ts  |  8 ++++++++
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/src/transactions/typeTag/index.ts b/src/transactions/typeTag/index.ts
index 2dd34e02f..9a7de8c8a 100644
--- a/src/transactions/typeTag/index.ts
+++ b/src/transactions/typeTag/index.ts
@@ -9,6 +9,7 @@ import { Serializable, Serializer } from "../../bcs/serializer";
 import { AccountAddress } from "../../core";
 import { Identifier } from "../instances/identifier";
 import { TypeTagVariants } from "../../types";
+import { APTOS_COIN } from "../../utils/const";
 
 export abstract class TypeTag extends Serializable {
   abstract serialize(serializer: Serializer): void;
@@ -224,7 +225,7 @@ export class TypeTagSigner extends TypeTag {
 }
 
 export class TypeTagReference extends TypeTag {
-  toString(): string {
+  toString(): `&${string}` {
     return `&${this.value.toString()}`;
   }
 
@@ -248,7 +249,7 @@ export class TypeTagReference extends TypeTag {
  * used as a type directly.
  */
 export class TypeTagGeneric extends TypeTag {
-  toString(): string {
+  toString(): `T${number}` {
     return `T${this.value}`;
   }
 
@@ -268,8 +269,8 @@ export class TypeTagGeneric extends TypeTag {
 }
 
 export class TypeTagVector extends TypeTag {
-  toString(): string {
-    return `vector${this.value.toString()}`;
+  toString(): `vector<${string}>` {
+    return `vector<${this.value.toString()}>`;
   }
 
   constructor(public readonly value: TypeTag) {
@@ -288,7 +289,7 @@ export class TypeTagVector extends TypeTag {
 }
 
 export class TypeTagStruct extends TypeTag {
-  toString(): string {
+  toString(): `0x${string}::${string}::${string}` {
     // Collect type args and add it if there are any
     let typePredicate = "";
     if (this.value.type_args.length > 0) {
@@ -368,8 +369,13 @@ export class StructTag extends Serializable {
   }
 }
 
-export const stringStructTag = () =>
-  new StructTag(AccountAddress.ONE, new Identifier("string"), new Identifier("String"), []);
+export function aptosCoinStructTag(): StructTag {
+  return new StructTag(AccountAddress.ONE, new Identifier("aptos_coin"), new Identifier("AptosCoin"), []);
+}
+
+export function stringStructTag(): StructTag {
+  return new StructTag(AccountAddress.ONE, new Identifier("string"), new Identifier("String"), []);
+}
 
 export function optionStructTag(typeArg: TypeTag): StructTag {
   return new StructTag(AccountAddress.ONE, new Identifier("option"), new Identifier("Option"), [typeArg]);
diff --git a/tests/unit/typeTagParser.test.ts b/tests/unit/typeTagParser.test.ts
index 7d9a13b07..297389dbc 100644
--- a/tests/unit/typeTagParser.test.ts
+++ b/tests/unit/typeTagParser.test.ts
@@ -24,8 +24,10 @@ import {
   TypeTagParserError,
   TypeTagParserErrorType,
   TypeTagReference,
+  aptosCoinStructTag,
 } from "../../src";
 import { Identifier } from "../../src/transactions/instances";
+import { APTOS_COIN } from "../../src/utils/const";
 
 const MODULE_NAME = new Identifier("tag");
 const STRUCT_NAME = new Identifier("Tag");
@@ -162,6 +164,12 @@ describe("TypeTagParser", () => {
     );
   });
 
+  test("aptos coin", () => {
+    const aptosCoin = new TypeTagStruct(aptosCoinStructTag());
+    expect(parseTypeTag("0x1::aptos_coin::AptosCoin")).toEqual(aptosCoin);
+    expect(parseTypeTag(APTOS_COIN)).toEqual(aptosCoin);
+  });
+
   test("string", () => {
     expect(parseTypeTag("0x1::string::String")).toEqual(new TypeTagStruct(stringStructTag()));
   });