Switch to ESLint v9 and flat config (#3558)

Since PR #3551 was not yet complete, I made my own attempt.

1. Update to ESLint v9.
2. Replace deprecated `.eslintrc.json` and `.eslintignore` by flat
config `eslint.config.mjs`.
3. Adapt `check_config.js` to use flat config.
4. Since `eslint-plugin-import` still doesn't support ESLint v9 I
removed it. We can add it back when it does support v9.
5. Run tests `npm run check:js` and `npm run config:check`.
6. In order not to overload this PR, I have not yet activated more
additional rules - there are some useful ones in the new plugin
`@eslint/js`.

@bugsounet, please don't take it as an offence that I have created a
competing PR. The migration to ESLint v9 has been burning under my nails
for some time.

.eslintignore

@@ -1,3 +0,0 @@
-modules/*
-!modules/default/
-js/positions.js

.eslintrc.json

@@ -1,94 +0,0 @@
-{
-	"extends": ["eslint:recommended", "plugin:@stylistic/all-extends", "plugin:import/recommended", "plugin:jest/recommended", "plugin:jsdoc/recommended"],
-	"plugins": ["unicorn"],
-	"env": {
-		"browser": true,
-		"es2024": true,
-		"jest/globals": true,
-		"node": true
-	},
-	"globals": {
-		"config": true,
-		"Log": true,
-		"MM": true,
-		"Module": true,
-		"moment": true
-	},
-	"parserOptions": {
-		"sourceType": "module",
-		"ecmaVersion": "latest",
-		"ecmaFeatures": {
-			"globalReturn": true
-		}
-	},
-	"rules": {
-		"eqeqeq": "error",
-		"import/order": "error",
-		"import/extensions": "error",
-		"import/newline-after-import": "error",
-		"jest/consistent-test-it": "warn",
-		"jest/expect-expect": "warn",
-		"jest/no-done-callback": "warn",
-		"jest/prefer-expect-resolves": "warn",
-		"jest/prefer-mock-promise-shorthand": "warn",
-		"jest/prefer-to-be": "warn",
-		"jest/prefer-to-have-length": "warn",
-		"no-param-reassign": "error",
-		"no-prototype-builtins": "off",
-		"no-throw-literal": "error",
-		"no-unused-vars": "off",
-		"no-useless-return": "error",
-		"object-shorthand": ["error", "methods"],
-		"prefer-template": "error",
-		"@stylistic/array-element-newline": ["error", "consistent"],
-		"@stylistic/arrow-parens": ["error", "always"],
-		"@stylistic/brace-style": "off",
-		"@stylistic/comma-dangle": ["error", "never"],
-		"@stylistic/dot-location": ["error", "property"],
-		"@stylistic/function-call-argument-newline": ["error", "consistent"],
-		"@stylistic/function-paren-newline": ["error", "consistent"],
-		"@stylistic/implicit-arrow-linebreak": ["error", "beside"],
-		"@stylistic/max-statements-per-line": ["error", { "max": 2 }],
-		"@stylistic/multiline-comment-style": "off",
-		"@stylistic/multiline-ternary": ["error", "always-multiline"],
-		"@stylistic/newline-per-chained-call": ["error", { "ignoreChainWithDepth": 4 }],
-		"@stylistic/no-extra-parens": "off",
-		"@stylistic/no-tabs": "off",
-		"@stylistic/object-curly-spacing": ["error", "always"],
-		"@stylistic/object-property-newline": ["error", { "allowAllPropertiesOnSameLine": true }],
-		"@stylistic/operator-linebreak": ["error", "before"],
-		"@stylistic/padded-blocks": "off",
-		"@stylistic/quote-props": ["error", "as-needed"],
-		"@stylistic/quotes": ["error", "double"],
-		"@stylistic/indent": ["error", "tab"],
-		"@stylistic/semi": ["error", "always"],
-		"@stylistic/space-before-function-paren": ["error", "always"],
-		"@stylistic/spaced-comment": "off",
-		"unicorn/prefer-node-protocol": "error"
-	},
-	"overrides": [
-		{
-			"files": ["config/config.js*"],
-			"rules": {
-				"@stylistic/comma-dangle": "off",
-				"@stylistic/indent": "off",
-				"@stylistic/no-multi-spaces": "off"
-			}
-		},
-		{
-			"files": ["tests/configs/modules/weather/*.js"],
-			"rules": {
-				"@stylistic/quotes": "off"
-			}
-		},
-		{
-			"extends": ["plugin:package-json/recommended"],
-			"files": ["package.json"],
-			"parser": "jsonc-eslint-parser",
-			"plugins": ["package-json"],
-			"rules": {
-				"package-json/sort-collections": ["error", ["devDependencies", "dependencies", "peerDependencies", "config"]]
-			}
-		}
-	]
-}

.github/CONTRIBUTING.md

@@ -12,7 +12,7 @@ We use prettier for automatic linting of all our files: `npm run lint:prettier`.
 
 We use [ESLint](https://eslint.org) on our JavaScript files.
 
-Our ESLint configuration is in our `.eslintrc.json` and `.eslintignore` files.
+The ESLint configuration is in our `eslint.config.mjs` file.
 
 To run ESLint, use `npm run lint:js`.
 

.prettierignore

@@ -1,5 +1,5 @@
 *.js
-.eslintignore
+*.mjs
 .husky/pre-commit
 .prettierignore
 /config

CHANGELOG.md

@@ -23,6 +23,7 @@ _This release is scheduled to be released on 2024-10-01._
 
 - [core] removed installer only files (#3492)
 - [core] removed raspberry object from systeminformation (#3505)
+- [linter] removed `eslint-plugin-import`, because it doesn't support ESLint v9. We will reenter it later when it does.
 
 ### Updated
 
@@ -32,6 +33,7 @@ _This release is scheduled to be released on 2024-10-01._
 - [core] Allow custom modules positions by scanning index.html for the defined regions, instead of hard coded (PR #3518 fixes issue #3504)
 - [core] Detail optimizations in `config_check.js`
 - [core] Updated minimal needed node version in `package.json` (currently v20.9.0)
+- [linter] Switch to ESLint v9 and flat config and replace `eslint-plugin-unicorn` by `@eslint/js`
 
 ### Fixed
 

eslint.config.mjs

@@ -0,0 +1,121 @@
+import eslintPluginJest from "eslint-plugin-jest";
+import eslintPluginJs from "@eslint/js";
+import eslintPluginStylistic from "@stylistic/eslint-plugin";
+import globals from "globals";
+
+const config = [
+	eslintPluginJs.configs.recommended,
+	{
+		files: ["**/*.js"],
+		languageOptions: {
+			ecmaVersion: "latest",
+			globals: {
+				...globals.browser,
+				...globals.node,
+				...globals.jest,
+				Log: "readonly",
+				MM: "readonly",
+				Module: "readonly",
+				config: "readonly",
+				moment: "readonly"
+			}
+		},
+		plugins: {
+			...eslintPluginStylistic.configs["all-flat"].plugins,
+			...eslintPluginJest.configs["flat/recommended"].plugins
+		},
+		rules: {
+			...eslintPluginStylistic.configs["all-flat"].rules,
+			...eslintPluginJest.configs["flat/recommended"].rules,
+			"@stylistic/array-element-newline": ["error", "consistent"],
+			"@stylistic/arrow-parens": ["error", "always"],
+			"@stylistic/brace-style": "off",
+			"@stylistic/comma-dangle": ["error", "never"],
+			"@stylistic/dot-location": ["error", "property"],
+			"@stylistic/function-call-argument-newline": ["error", "consistent"],
+			"@stylistic/function-paren-newline": ["error", "consistent"],
+			"@stylistic/implicit-arrow-linebreak": ["error", "beside"],
+			"@stylistic/indent": ["error", "tab"],
+			"@stylistic/max-statements-per-line": ["error", {max: 2}],
+			"@stylistic/multiline-comment-style": "off",
+			"@stylistic/multiline-ternary": ["error", "always-multiline"],
+			"@stylistic/newline-per-chained-call": ["error", {ignoreChainWithDepth: 4}],
+			"@stylistic/no-extra-parens": "off",
+			"@stylistic/no-tabs": "off",
+			"@stylistic/object-curly-spacing": ["error", "always"],
+			"@stylistic/object-property-newline": ["error", {allowAllPropertiesOnSameLine: true}],
+			"@stylistic/operator-linebreak": ["error", "before"],
+			"@stylistic/padded-blocks": "off",
+			"@stylistic/quote-props": ["error", "as-needed"],
+			"@stylistic/quotes": ["error", "double"],
+			"@stylistic/semi": ["error", "always"],
+			"@stylistic/space-before-function-paren": ["error", "always"],
+			"@stylistic/spaced-comment": "off",
+			eqeqeq: "error",
+			"id-length": "off",
+			"init-declarations": "off",
+			"jest/consistent-test-it": "warn",
+			"jest/no-done-callback": "warn",
+			"jest/prefer-expect-resolves": "warn",
+			"jest/prefer-mock-promise-shorthand": "warn",
+			"jest/prefer-to-be": "warn",
+			"jest/prefer-to-have-length": "warn",
+			"max-lines-per-function": ["warn", 350],
+			"max-statements": "off",
+			"no-global-assign": "off",
+			"no-inline-comments": "off",
+			"no-magic-numbers": "off",
+			"no-param-reassign": "error",
+			"no-plusplus": "off",
+			"no-prototype-builtins": "off",
+			"no-ternary": "off",
+			"no-throw-literal": "error",
+			"no-undefined": "off",
+			"no-unused-vars": "off",
+			"no-useless-return": "error",
+			"no-warning-comments": "off",
+			"object-shorthand": ["error", "methods"],
+			"one-var": "off",
+			"prefer-destructuring": "off",
+			"prefer-template": "error",
+			"sort-keys": "off"
+		}
+	},
+	{
+		files: ["**/*.mjs"],
+		languageOptions: {
+			ecmaVersion: "latest",
+			globals: {
+				...globals.node
+			},
+			sourceType: "module"
+		},
+		plugins: {
+			...eslintPluginStylistic.configs["all-flat"].plugins
+		},
+		rules: {
+			...eslintPluginStylistic.configs["all-flat"].rules,
+			"@stylistic/array-element-newline": "off",
+			"@stylistic/indent": ["error", "tab"],
+			"@stylistic/padded-blocks": ["error", "never"],
+			"@stylistic/quote-props": ["error", "as-needed"],
+			"func-style": "off",
+			"import/namespace": "off",
+			"max-lines-per-function": ["error", 100],
+			"no-magic-numbers": "off",
+			"one-var": "off",
+			"prefer-destructuring": "off"
+		}
+	},
+	{
+		files: ["tests/configs/modules/weather/*.js"],
+		rules: {
+			"@stylistic/quotes": "off"
+		}
+	},
+	{
+		ignores: ["config/**", "modules/**", "!modules/default/**", "js/positions.js"]
+	}
+];
+
+export default config;

js/check_config.js

@@ -2,13 +2,14 @@ const path = require("node:path");
 const fs = require("node:fs");
 const Ajv = require("ajv");
 const colors = require("ansis");
+const globals = require("globals");
 const { Linter } = require("eslint");
 
 const rootPath = path.resolve(`${__dirname}/../`);
 const Log = require(`${rootPath}/js/logger.js`);
 const Utils = require(`${rootPath}/js/utils.js`);
 
-const linter = new Linter();
+const linter = new Linter({ configType: "flat" });
 const ajv = new Ajv();
 
 /**
@@ -29,16 +30,14 @@ function checkConfigFile () {
 
 	// Check if file is present
 	if (fs.existsSync(configFileName) === false) {
-		Log.error(`File not found: ${configFileName}`);
+		throw new Error(`File not found: ${configFileName}\nNo config file present!`);
-		throw new Error("No config file present!");
 	}
 
 	// Check permission
 	try {
 		fs.accessSync(configFileName, fs.F_OK);
 	} catch (error) {
-		Log.error(error);
+		throw new Error(`${error}\nNo permission to access config file!`);
-		throw new Error("No permission to access config file!");
 	}
 
 	// Validate syntax of the configuration file.
@@ -47,30 +46,39 @@ function checkConfigFile () {
 	// I'm not sure if all ever is utf-8
 	const configFile = fs.readFileSync(configFileName, "utf-8");
 
-	// Explicitly tell linter that he might encounter es2024 syntax ("let config = {...}")
+	const errors = linter.verify(
-	const errors = linter.verify(configFile, {
+		configFile,
-		env: {
+		{
-			es2024: true
+			languageOptions: {
+				ecmaVersion: "latest",
+				globals: {
+					...globals.node
 				}
-	});
+			}
+		},
+		configFileName
+	);
 
 	if (errors.length === 0) {
 		Log.info(colors.green("Your configuration file doesn't contain syntax errors :)"));
+		validateModulePositions(configFileName);
 	} else {
-		Log.error("Your configuration file contains syntax errors :(");
+		let errorMessage = "Your configuration file contains syntax errors :(";
 
 		for (const error of errors) {
-			Log.error(`Line ${error.line} column ${error.column}: ${error.message}`);
+			errorMessage += `\nLine ${error.line} column ${error.column}: ${error.message}`;
+		}
+		throw new Error(errorMessage);
 	}
-		process.exit(1);
 }
 
+function validateModulePositions (configFileName) {
 	Log.info("Checking modules structure configuration ...");
 
 	const positionList = Utils.getModulePositions();
 
 	// Make Ajv schema configuration of modules config
-	// only scan "module" and "position"
+	// Only scan "module" and "position"
 	const schema = {
 		type: "object",
 		properties: {
@@ -103,16 +111,21 @@ function checkConfigFile () {
 	} else {
 		const module = validate.errors[0].instancePath.split("/")[2];
 		const position = validate.errors[0].instancePath.split("/")[3];
-
+		let errorMessage = "This module configuration contains errors:";
-		Log.error("This module configuration contains errors:");
+		errorMessage += `\n${JSON.stringify(data.modules[module], null, 2)}`;
-		Log.error(`\n${JSON.stringify(data.modules[module], null, 2)}`);
 		if (position) {
-			Log.error(`${position}: ${validate.errors[0].message}`);
+			errorMessage += `\n${position}: ${validate.errors[0].message}`;
-			Log.error(`\n${JSON.stringify(validate.errors[0].params.allowedValues, null, 2).slice(1, -1)}`);
+			errorMessage += `\n${JSON.stringify(validate.errors[0].params.allowedValues, null, 2).slice(1, -1)}`;
 		} else {
-			Log.error(validate.errors[0].message);
+			errorMessage += validate.errors[0].message;
 		}
+		Log.error(errorMessage);
 	}
 }
 
+try {
 	checkConfigFile();
+} catch (error) {
+	Log.error(error.message);
+	process.exit(1);
+}

package.json

@@ -59,7 +59,7 @@
 		"ansis": "^3.3.2",
 		"console-stamp": "^3.1.2",
 		"envsub": "^4.1.0",
-		"eslint": "^8.57.0",
+		"eslint": "^9.11.1",
 		"express": "^4.21.0",
 		"express-ipfilter": "^1.3.2",
 		"feedme": "^2.0.2",
@@ -75,13 +75,12 @@
 		"systeminformation": "^5.23.5"
 	},
 	"devDependencies": {
+		"@eslint/js": "^9.11.1",
 		"@stylistic/eslint-plugin": "^2.8.0",
 		"cspell": "^8.14.4",
-		"eslint-plugin-import": "^2.30.0",
 		"eslint-plugin-jest": "^28.8.3",
 		"eslint-plugin-jsdoc": "^50.2.4",
 		"eslint-plugin-package-json": "^0.15.3",
-		"eslint-plugin-unicorn": "^55.0.0",
 		"express-basic-auth": "^1.2.1",
 		"husky": "^9.1.6",
 		"jest": "^29.7.0",

tests/unit/functions/server_functions_spec.js

@@ -19,7 +19,7 @@ describe("server_functions tests", () => {
 				},
 				text: fetchResponseHeadersText
 			};
-			// eslint-disable-next-line
+
 			fetch = jest.fn();
 			fetch.mockImplementation(() => fetchResponse);