Various updates and upgrades to lots of packages. (#22)

Apply prefer-const.

.gitignore

@@ -3,3 +3,4 @@ node_modules
 npm-debug.log
 out
 .DS_Store
+.vscode-test

eslint.config.js

@@ -0,0 +1,48 @@
+const typescriptParser = require('@typescript-eslint/parser');
+const typescriptPlugin = require('@typescript-eslint/eslint-plugin');
+
+module.exports = [
+    {
+        ignores: ["**/out", "**/dist", "**/*.d.ts"]
+    },
+    {
+        files: [
+            "src/*.ts",
+            "src/**/*.ts"
+        ],
+        ignores: [
+            "eslint.config.js"
+        ],
+        plugins: {
+            "@typescript-eslint": typescriptPlugin
+        },
+
+        languageOptions: {
+            sourceType: "module",
+            parser: typescriptParser,
+            parserOptions: {
+                ecmaVersion: 2020
+            }
+        },
+
+        rules: {
+            "@typescript-eslint/naming-convention": "warn",
+            curly: "warn",
+            eqeqeq: "warn",
+            "no-throw-literal": "warn",
+            semi: "error",
+            "prefer-const": "error"
+        }
+    },
+    {
+        files: [
+            "src/*.ts",
+            "src/**/*.ts"
+        ],
+        languageOptions: {
+            parserOptions: {
+                project: ["./tsconfig.json"]
+            }
+        }
+    }
+];