Add getBalance method to Network type (#56)

* Add getBalance method to Network type

* Add getBalance method to Network stub

* Add getBalance method to ethers Network

* Fix address type

* Add getBalance method to viem Network

* Add changeset

.changeset/green-ghosts-hammer.md

@@ -0,0 +1,7 @@
+---
+"@delvtech/evm-client-ethers": minor
+"@delvtech/evm-client-viem": minor
+"@delvtech/evm-client": minor
+---
+
+Add a getBalance method to the Network interface for fetching native currency balances (e.g. ETH)

packages/evm-client-ethers/src/network/createNetwork.ts

@@ -3,6 +3,15 @@ import { Provider } from 'ethers';
 
 export function createNetwork(provider: Provider): Network {
   return {
+    async getBalance(account, options = {}) {
+      const { blockHash, blockNumber, blockTag } = options;
+
+      return provider.getBalance(
+        account,
+        blockHash || blockNumber || blockTag || 'latest',
+      );
+    },
+
     async getBlock(options = {}) {
       const { blockHash, blockNumber, blockTag } = options;
 

packages/evm-client-viem/src/network/createNetwork.ts

@@ -1,8 +1,32 @@
 import { Network } from '@delvtech/evm-client';
-import { PublicClient, TransactionLegacy, rpcTransactionType } from 'viem';
+import {
+  GetBalanceParameters,
+  PublicClient,
+  TransactionLegacy,
+  rpcTransactionType,
+} from 'viem';
 
 export function createNetwork(publicClient: PublicClient): Network {
   return {
+    async getBalance(account, options) {
+      const { blockHash, blockNumber, blockTag } = options ?? {};
+
+      const parameters: Partial<GetBalanceParameters> = {
+        address: account,
+      };
+
+      if (blockNumber) {
+        parameters.blockNumber = blockNumber;
+      } else if (blockTag) {
+        parameters.blockTag = blockHash;
+      } else if (blockHash) {
+        const block = await publicClient.getBlock({ blockHash });
+        parameters.blockNumber = block.number;
+      }
+
+      return publicClient.getBalance(parameters as GetBalanceParameters);
+    },
+
     async getBlock(args) {
       const block = await publicClient.getBlock(args);
 

packages/evm-client/src/exports/network.ts

@@ -1,9 +1,11 @@
 export type { Block, BlockTag } from 'src/network/types/Block';
 export type {
   Network,
+  NetworkGetBalanceArgs,
   NetworkGetBlockArgs,
   NetworkGetBlockOptions,
   NetworkGetTransactionArgs,
+  NetworkWaitForTransactionArgs,
 } from 'src/network/types/Network';
 export type {
   MinedTransaction,

packages/evm-client/src/network/stubs/NetworkStub.ts

@@ -2,6 +2,7 @@ import { SinonStub, stub } from 'sinon';
 import { Block } from 'src/network/types/Block';
 import {
   Network,
+  NetworkGetBalanceArgs,
   NetworkGetBlockArgs,
   NetworkGetTransactionArgs,
   NetworkWaitForTransactionArgs,
@@ -13,13 +14,36 @@ import { Transaction, TransactionReceipt } from 'src/network/types/Transaction';
  * testing.
  */
 export class NetworkStub implements Network {
+  protected getBalanceStub:
+    | SinonStub<[NetworkGetBalanceArgs?], Promise<bigint>>
+    | undefined;
   protected getBlockStub:
     | SinonStub<[NetworkGetBlockArgs?], Promise<Block | undefined>>
     | undefined;
   protected getTransactionStub:
     | SinonStub<[NetworkGetTransactionArgs?], Promise<Transaction | undefined>>
     | undefined;
 
+  stubGetBalance({
+    args,
+    value,
+  }: {
+    args?: NetworkGetBalanceArgs | undefined;
+    value: bigint;
+  }): void {
+    if (!this.getBalanceStub) {
+      this.getBalanceStub = stub();
+    }
+
+    // Account for dynamic args if provided
+    if (args) {
+      this.getBalanceStub.withArgs(args).resolves(value);
+      return;
+    }
+
+    this.getBalanceStub.resolves(value);
+  }
+
   stubGetBlock({
     args,
     value,
@@ -60,6 +84,15 @@ export class NetworkStub implements Network {
     this.getTransactionStub.resolves(value);
   }
 
+  getBalance(...args: NetworkGetBalanceArgs): Promise<bigint> {
+    if (!this.getBalanceStub) {
+      throw new Error(
+        `The getBalance function must be stubbed first:\n\tcontract.stubGetBalance()`,
+      );
+    }
+    return this.getBalanceStub(args);
+  }
+
   getBlock(...args: NetworkGetBlockArgs): Promise<Block | undefined> {
     if (!this.getBlockStub) {
       throw new Error(

packages/evm-client/src/network/types/Network.ts

@@ -7,6 +7,11 @@ import { Transaction, TransactionReceipt } from 'src/network/types/Transaction';
  * An interface representing data the SDK needs to get from the network.
  */
 export interface Network {
+  /**
+   * Get the balance of native currency for an account.
+   */
+  getBalance(...args: NetworkGetBalanceArgs): Promise<bigint>;
+
   /**
    * Get a block from a block tag, number, or hash. If no argument is provided,
    * the latest block is returned.
@@ -45,6 +50,11 @@ export type NetworkGetBlockOptions =
       blockTag?: BlockTag;
     };
 
+export type NetworkGetBalanceArgs = [
+  address: `0x${string}`,
+  block?: NetworkGetBlockOptions,
+];
+
 export type NetworkGetBlockArgs = [options?: NetworkGetBlockOptions];
 
 export type NetworkGetTransactionArgs = [hash: `0x${string}`];