[TypeScript] Lint TypeScipt code (#736)

Currently the typescript code is not being linted in the CI. This PR adds some basic recommended typescript linting rules and fixes to code so that the linting succeeds.

In order to fix an import lint on importing `truffle-assertions`, I added some typings for the module.

### Test Plan

CI - linting should succeed.

### Commit History

* ignore fewer files

* lint TS files

.eslintrc.js

@@ -1,34 +1,41 @@
 module.exports = {
+  root: true,
   parser: "@typescript-eslint/parser",
   env: {
-    browser: true,
+    node: true,
     commonjs: true,
     es2020: true,
   },
-  extends: "eslint:recommended",
+  extends: ["eslint:recommended", "plugin:@typescript-eslint/eslint-recommended", "plugin:@typescript-eslint/recommended"],
   parserOptions: {
-    ecmaFeatures: {
-      jsx: true,
-    },
     ecmaVersion: 2015,
     sourceType: "module",
   },
-  plugins: ["react", "@typescript-eslint"],
+  plugins: ["@typescript-eslint"],
   rules: {
     indent: ["error", 2],
     "linebreak-style": ["error", "unix"],
+    "no-console": "error",
     quotes: ["error", "double"],
     semi: ["error", "never"],
-    "prefer-const": ["error"],
-    "no-var": ["error"],
 
-    "no-unused-vars": "off",
-    "@typescript-eslint/no-unused-vars": ["error"],
+    "@typescript-eslint/camelcase": "off",
+    "@typescript-eslint/no-use-before-define": "off",
   },
   globals: {
     artifacts: false,
     contract: false,
     assert: false,
     web3: false,
   },
+  overrides: [
+    {
+      files: ["*.js"],
+      rules: {
+        "@typescript-eslint/explicit-function-return-type": "off",
+        "@typescript-eslint/no-var-requires": "off",
+      },
+    },
+  ],
+  ignorePatterns: ["build/", "coverage/", "node_modules/"],
 }

migration_conf.js

@@ -1,8 +1,6 @@
 const path = require("path")
 
-// eslint-disable-next-line no-undef
 const BUILD_DIR = path.join(__dirname, "build", "contracts")
-// eslint-disable-next-line no-undef
 const NETWORKS_FILE_PATH = path.join(__dirname, "networks.json")
 
 module.exports = {

package.json

@@ -21,7 +21,7 @@
     "networks-inject": "CONF_FILE=$(pwd)'/migration_conf.js'  node node_modules/@gnosis.pm/util-contracts/src/inject_network_info.js",
     "networks-reset": "mkdir -p build/contracts && truffle networks --clean && yarn run networks-inject",
     "verify-stablex": "truffle run verify BatchExchange",
-    "lint": "eslint .",
+    "lint": "eslint . --ext .js,.ts",
     "solhint": "solhint \"contracts/**/*.sol\"",
     "prepack": "yarn run build",
     "prettier:solidity": "prettier --write 'contracts/**/*.sol'",
@@ -91,7 +91,6 @@
     "dotenv": "^8.2.0",
     "eslint": "^6.8.0",
     "eslint-plugin-no-only-tests": "^2.4.0",
-    "eslint-plugin-react": "^7.19.0",
     "eth-gas-reporter": "^0.2.17",
     "ganache-cli": "^6.9.1",
     "husky": "^4.2.5",
@@ -117,6 +116,7 @@
     "web3": "^1.2.7",
     "web3-core": "^1.2.7",
     "web3-eth-contract": "^1.2.7",
+    "web3-utils": "^1.2.7",
     "yargs": "^15.3.1"
   }
 }

scripts/.eslintrc.js

@@ -2,8 +2,4 @@ module.exports = {
   rules: {
     "no-console": "off",
   },
-  env: {
-    mocha: true,
-    node: true,
-  },
 }

src/balance_reader.ts

@@ -1,8 +1,8 @@
-import BN from "bn.js";
-import Web3 from "web3";
-import {BatchExchangeInstance} from "../types/truffle-typings";
+import BN from "bn.js"
+import Web3 from "web3"
+import {BatchExchangeInstance} from "../types/truffle-typings"
 
-const WORD_DATA_LENGTH = 64;
+const WORD_DATA_LENGTH = 64
 
 /**
  * Retrieves user's token balance as stored in the "balance" entry of the private exchange mapping balanceStates
@@ -22,7 +22,7 @@ export async function getBalanceState(
 ): Promise<BN> {
   // TODO when Truffle depends on web3-utils version ^1.2.5:
   // use soliditySha3Raw instead of soliditySha3 and remove type coercion
-  const BALANCESTATES_STORAGE_SLOT = "0x0";
+  const BALANCESTATES_STORAGE_SLOT = "0x0"
 
   const userBalancestatesStorageSlot = web3Provider.utils.soliditySha3(
     {
@@ -36,7 +36,7 @@ export async function getBalanceState(
         WORD_DATA_LENGTH
       ),
     }
-  ) as string;
+  ) as string
 
   const targetStorageSlot = web3Provider.utils.soliditySha3(
     {
@@ -50,13 +50,13 @@ export async function getBalanceState(
         WORD_DATA_LENGTH
       ),
     }
-  ) as string;
+  ) as string
 
   const storageAtSlot = await web3Provider.eth.getStorageAt(
     batchExchangeAddress,
     targetStorageSlot
-  );
-  return web3Provider.utils.toBN(storageAtSlot);
+  )
+  return web3Provider.utils.toBN(storageAtSlot)
 }
 
 /**
@@ -92,14 +92,14 @@ export async function getWithdrawableAmount(
     batchExchange.getPendingWithdraw(userAddress, tokenAddress),
     batchExchange.lastCreditBatchId(userAddress, tokenAddress),
     batchExchange.getCurrentBatchId(),
-  ]);
-  let balance = balanceState;
+  ])
+  let balance = balanceState
   if (pendingDeposit[1].lt(batchId)) {
-    balance = balance.add(pendingDeposit[0]);
+    balance = balance.add(pendingDeposit[0])
   }
   if (pendingWithdrawal[1].gte(batchId) || lastCreditBatchId.gte(batchId)) {
-    return new BN(0);
+    return new BN(0)
   } else {
-    return BN.min(balance, pendingWithdrawal[0]);
+    return BN.min(balance, pendingWithdrawal[0])
   }
 }