Migrate eslint from 8 to 9 using flat configs

eslint.config.mjs

@@ -0,0 +1,49 @@
+// @ts-check
+
+import globals from 'globals';
+import eslint from '@eslint/js';
+import tseslint from 'typescript-eslint';
+
+export default tseslint.config(
+	eslint.configs.recommended,
+	...tseslint.configs.strict,
+	...tseslint.configs.stylistic,
+	{
+		// Javascript specific config
+		files: ['**/*.js'],
+		rules: {
+			'indent': ['error', 'tab'],
+			'@typescript-eslint/no-require-imports': ['off'],
+		},
+		languageOptions: {
+			globals: {
+				...globals.node,
+				...globals.browser,
+			},
+			ecmaVersion: 6,
+		},
+	},
+	{
+		// Typescript specific config
+		files: ['**/*.ts'],
+		rules: {
+			'@typescript-eslint/consistent-type-definitions': ['off'],
+		},
+	},
+	{
+		// Test specific config
+		files: ['**/*.test.ts'],
+		rules: {},
+	},
+	{
+		ignores: [
+			'.cache/',
+			'.parcel-cache/',
+			'coverage/',
+			'node_modules/',
+			'public/',
+			'dist/',
+			'web/',
+		],
+	}
+);