feat: add function to get token balance from metamask

.gitignore

@@ -4,7 +4,7 @@ test/server/data.js
 build
 dist
 .vscode/
-metamask
+/metamask
 .idea
 *.log
 test/dapp/data.js

src/index.ts

@@ -37,6 +37,7 @@ export type Dappeteer = {
   sign: () => Promise<void>;
   approve: () => Promise<void>;
   addToken: (tokenAddress: string) => Promise<void>;
+  getTokenBalance: (tokenSymbol: string) => Promise<number>;
   page: Page;
 };
 

src/metamask/getTokenBalance.ts

@@ -0,0 +1,21 @@
+import { Page } from 'puppeteer';
+
+export const getTokenBalance = (page: Page) => async (tokenSymbol: string): Promise<number> => {
+  await page.bringToFront();
+  await page.waitForTimeout(1000);
+
+  const assetListItems = await page.$$('.asset-list-item__token-button');
+
+  for (let index = 0; index < assetListItems.length; index++) {
+    const assetListItem = assetListItems[index];
+
+    const titleAttributeValue: string = await page.evaluate((item) => item.getAttribute('title'), assetListItem);
+
+    if (titleAttributeValue.split(' ')[1].toUpperCase() === tokenSymbol.toUpperCase()) {
+      const balance = titleAttributeValue.split(' ')[0];
+      return parseFloat(balance);
+    }
+  }
+
+  return 0;
+};

src/metamask/index.ts

@@ -6,6 +6,7 @@ import { addNetwork } from './addNetwork';
 import { addToken } from './addToken';
 import { approve } from './approve';
 import { confirmTransaction } from './confirmTransaction';
+import { getTokenBalance } from './getTokenBalance';
 import { importPk } from './importPk';
 import { lock } from './lock';
 import { sign } from './sign';
@@ -41,6 +42,7 @@ export const getMetamask = async (page: Page, version?: string): Promise<Dappete
     switchNetwork: switchNetwork(page, version),
     unlock: unlock(page, setSignedIn, getSingedIn, version),
     addToken: addToken(page),
+    getTokenBalance: getTokenBalance(page),
     page,
   };
 };