Start of linting, testing, and refactoring

.eslintrc.json

@@ -0,0 +1,69 @@
+{
+  "env": {
+    "browser": true,
+    "es2021": true
+  },
+  "extends": [
+    "plugin:react/recommended",
+    "airbnb",
+    "airbnb-typescript",
+    "eslint:recommended"
+  ],
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "ecmaFeatures": {
+      "jsx": true
+    },
+    "ecmaVersion": "latest",
+    "sourceType": "module",
+    "project": "./tsconfig.json"
+  },
+  "plugins": [
+    "react",
+    "@typescript-eslint"
+  ],
+  "rules": {
+    "no-restricted-syntax": [
+      "error",
+      "ForInStatement"
+    ],
+    "no-param-reassign": [
+      "error",
+      {
+        "props": false
+      }
+    ],
+    "max-len": [
+      "error",
+      {
+        "ignoreComments": true,
+        "code": 120
+      }
+    ],
+    "import/extensions": [
+      1,
+      "never",
+      {
+        "tsx": "never",
+        "json": "always"
+      }
+    ],
+    "react/jsx-filename-extension": [
+      1,
+      {
+        "extensions": [
+          ".js",
+          ".jsx",
+          ".tsx"
+        ]
+      }
+    ],
+    "react/function-component-definition": [
+      "error",
+      {
+        "namedComponents": "arrow-function",
+        "unnamedComponents": "arrow-function"
+      }
+    ]
+  }
+}

.vscode/settings.json

@@ -5,5 +5,7 @@
         "preload",
         "uuidv"
     ],
-    "typescript.tsdk": "node_modules/typescript/lib"
+    "typescript.tsdk": "node_modules/typescript/lib",
+    "editor.tabSize": 2,
+    "editor.detectIndentation": false
 }

jest.config.js

@@ -0,0 +1,5 @@
+/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+};