Created eslint+prettier config

Author: usmt-cop

.eslintrc.js

@@ -0,0 +1,35 @@
+// .eslintrc.js
+
+module.exports = {
+    parser: '@typescript-eslint/parser',
+    extends: [
+        'eslint:recommended',
+        'plugin:@typescript-eslint/recommended',
+        'plugin:@typescript-eslint/recommended-requiring-type-checking'
+    ],
+    parserOptions: {
+        ecmaVersion: 2020,
+        sourceType: 'module',
+        tsconfigRootDir: __dirname,
+        project: ['./tsconfig.json'],
+        extraFileExtensions: ['.svelte']
+    },
+    env: {
+        es6: true,
+        browser: true
+    },
+    overrides: [
+        {
+            files: ['*.svelte'],
+            processor: 'svelte3/svelte3'
+        }
+    ],
+    settings: {
+        'svelte3/typescript': require('typescript'),
+        // ignore style tags in Svelte because of Tailwind CSS
+        // See https://github.com/sveltejs/eslint-plugin-svelte3/issues/70
+        'svelte3/ignore-styles': () => true
+    },
+    plugins: ['svelte3', '@typescript-eslint'],
+    ignorePatterns: ['node_modules']
+}

.prettierignore

@@ -0,0 +1 @@
+public/build

package.json

@@ -13,7 +13,10 @@
     "dev": "rollup -c -w",
     "start": "sirv public --no-clear",
     "check": "svelte-check --tsconfig ./tsconfig.json",
-    "test": "TZ=America/Los_Angeles jest"
+    "test": "TZ=America/Los_Angeles jest",
+    "format": "prettier --write ./src/**/*.{js,svelte,html,ts}",
+    "lint": "eslint src  --ext .js,.svelte,.html,.ts",
+    "lint:fix": "eslint --fix src --ext .js,.svelte"
   },
   "devDependencies": {
     "@rollup/plugin-commonjs": "^17.0.0",
@@ -23,7 +26,13 @@
     "@types/firebase": "^3.2.1",
     "@types/jest": "^27.0.3",
     "@types/node": "^16.11.9",
+    "@typescript-eslint/eslint-plugin": "^5.44.0",
+    "@typescript-eslint/parser": "^5.44.0",
+    "eslint": "^8.28.0",
+    "eslint-plugin-svelte3": "^4.0.0",
     "jest": "^27.3.1",
+    "prettier": "^2.7.1",
+    "prettier-plugin-svelte": "^2.8.1",
     "rollup": "^2.3.4",
     "rollup-plugin-css-only": "^3.1.0",
     "rollup-plugin-livereload": "^2.0.0",