Contract Linting: add lint:types and use @typescript/eslint-parser

[0xpatrickdev]

Building off of #33, update the eslint configuration to use @typescript/eslint-parser. With this in place, we can use typescript to audit jsdoc typedefs and enable better code navigation (go to definition).

[0xpatrickdev]

See this comments for more details on a suggested eslint configuration: #26 (comment)

Here would be the updated directions from the current answer:

1. Run:

yarn add -D \
 eslint \
 @agoric/eslint-config@dev \
 @endo/eslint-plugin \
 @jessie.js/eslint-plugin \
  eslint-config-airbnb-base \
 eslint-plugin-jsdoc \
 eslint-config-prettier \
 eslint-plugin-import \
- eslint-plugin-github 
+ eslint-plugin-github \
+ @typescript-eslint/eslint-plugin
+ @typescript-eslint/parser
+ typescript

2. Add the following to your package.json

 "eslintConfig" : {
+  "env": {
+    "node": true
+  },
+  "parser": "@typescript-eslint/parser",
   "parserOptions": {
-      "sourceType": "module",
-      "ecmaVersion": 6
+    "project": "./tsconfig.json",
+    "sourceType": "module",
+    "ecmaVersion": 2020
   },
   "extends": [
+    "plugin:@typescript-eslint/recommended",
     "@agoric"
   ],
+  "plugins": [
+    "@typescript-eslint",
+    "prettier"
+  ],
+  "rules": {
+    "@typescript-eslint/no-floating-promises": "warn",
+    "no-void": [
+      "error",
+      {
+        "allowAsStatement": true
+      }
+    ],
+    "prettier/prettier": "warn",
+    "@typescript-eslint/no-unused-vars": [
+      "error",
+      {
+        "vars": "all",
+        "args": "all",
+        "argsIgnorePattern": "^_",
+        "varsIgnorePattern": "^_"
+      }
+    ]
+  },
 }

3. Add a tsconfig.json file (new)

+{
+  "compilerOptions": {
+    "noEmit": true,
+    "target": "esnext",
+    "module": "esnext",
+    "moduleResolution": "node",
+    "skipLibCheck": true,
+    "checkJs": false,
+    "allowJs": true,
+    "allowSyntheticDefaultImports": true,
+    "maxNodeModuleJsDepth": 2,
+    "strict": true
+  },
+  "include": ["**/*.js", "**/*.ts"],
+  "exclude": ["bundles"]
+}

4. Run yarn eslint '**/*.{js,ts}' (or specify other files/directory globs). Run yarn tsc to lint types.