Upgrade eslint to 9

config/grunt/custom-tasks/sync-gutenberg-version.js

@@ -10,7 +10,7 @@ module.exports = function( grunt ) {
 	 *
 	 * @returns {void}
 	 */
-	 function setVersion( file, pattern, version ) {
+	function setVersion( file, pattern, version ) {
 		const contents = grunt.file.read( file ).replace(
 			pattern,
 			version

eslint.config.mjs

@@ -0,0 +1,40 @@
+import globals from "globals";
+import yoastConfig from "eslint-config-yoast";
+
+/** @type {import('eslint').Linter.Config[]} */
+export default [
+	{ ignores: [ "js/dist", "packages", "apps", "artifact", "vendor", "vendor_prefixed", ".yarn" ] },
+	...yoastConfig,
+	{
+		languageOptions: {
+			ecmaVersion: "latest",
+			globals: {
+				...globals.browser,
+			},
+		},
+		rules: {
+			// Deviate from the Yoast config to prohibit dangling commas in functions.
+			"stylistic/comma-dangle": [
+				"error",
+				{
+					functions: "never",
+					arrays: "always-multiline",
+					objects: "always-multiline",
+					imports: "always-multiline",
+					exports: "always-multiline",
+				},
+			],
+
+			// Deviate from the Yoast config to allow for not using the error that is caught.
+			"no-unused-vars": [ "error", { caughtErrors: "none" } ],
+		},
+	},
+	{
+		files: [ "*.config.js", "config/**", "Gruntfile.js" ],
+		languageOptions: {
+			globals: {
+				...globals.node,
+			},
+		},
+	},
+];

package.json

@@ -55,11 +55,9 @@
     "core-js": "^2.6.12",
     "cross-env": "^7.0.3",
     "dotenv": "^8.2.0",
-    "eslint": "^8.57.0",
+    "eslint": "^9.16.0",
     "eslint-config-yoast": "^6.0.0",
-    "eslint-plugin-import": "^2.29.1",
-    "eslint-plugin-jsx-a11y": "^6.8.0",
-    "eslint-plugin-react": "^7.34.1",
+    "globals": "^15.13.0",
     "grunt-git": "^1.0.14",
     "grunt-prompt": "^1.3.3",
     "grunt-shell": "^3.0.1",

packages/analysis-report/eslint.config.mjs

@@ -0,0 +1,55 @@
+import globals from "globals";
+import yoastConfig, { reactConfig } from "eslint-config-yoast";
+
+/** @type {import('eslint').Linter.Config[]} */
+export default [
+	{ ignores: [ "build" ] },
+	...yoastConfig,
+	...reactConfig,
+	{
+		languageOptions: {
+			ecmaVersion: "latest",
+			globals: {
+				...globals.browser,
+			},
+		},
+		rules: {
+			// Account for webpack externals and potentially unbuilt packages in the monorepo setup.
+			"import/no-unresolved": [
+				"error",
+				{
+					ignore: [
+						// Ignore @yoast packages from this workspace, or we have to build the code before linting.
+						// Because `main` in `package.json` points to the `build/index.js`, which is not present before building.
+						// As we are dealing with our source, not the actual NPM download, due to the monorepo setup.
+						"^@yoast/(ui-library|style-guide|components|helpers|search-metadata-previews|social-metadata-forms|replacement-variable-editor|analysis-report|feature-flag|related-keyphrase-suggestions)$",
+						"yoastseo",
+					],
+				},
+			],
+
+			// Deviate from the Yoast config to prohibit dangling commas in functions.
+			"stylistic/comma-dangle": [
+				"error",
+				{
+					functions: "never",
+					arrays: "always-multiline",
+					objects: "always-multiline",
+					imports: "always-multiline",
+					exports: "always-multiline",
+				},
+			],
+
+			// Deviate from the Yoast config to allow existing violations. New occurrences are still disallowed.
+			"react/jsx-no-bind": "warn",
+		},
+	},
+	{
+		files: [ "*.config.js", "tools/jest/**" ],
+		languageOptions: {
+			globals: {
+				...globals.node,
+			},
+		},
+	},
+];

packages/analysis-report/package.json

@@ -36,11 +36,9 @@
     "@yoast/babel-preset": "^1.1.1",
     "@yoast/jest-preset": "^1.0.1",
     "babel-plugin-styled-components": "^2.0.6",
-    "eslint": "^8.57.0",
+    "eslint": "^9.16.0",
     "eslint-config-yoast": "^6.0.0",
-    "eslint-plugin-import": "^2.29.1",
-    "eslint-plugin-jsx-a11y": "^6.8.0",
-    "eslint-plugin-react": "^7.34.1",
+    "globals": "^15.13.0",
     "jest": "^27.5.1",
     "jest-styled-components": "^7.0.8",
     "react-test-renderer": "^18.2.0"

packages/analysis-report/src/AnalysisResult.js

@@ -1,4 +1,3 @@
-/* eslint-disable complexity */
 import React, { useCallback, useEffect, useState } from "react";
 import PropTypes from "prop-types";
 import styled from "styled-components";

packages/analysis-report/tests/__mocks__/@wordpress/i18n.js

@@ -1,4 +1,4 @@
-/* eslint-disable require-jsdoc */
+/* eslint-disable jsdoc/require-jsdoc */
 
 import { sprintf, setLocaleData } from "@wordpress/i18n";
 

packages/browserslist-config/eslint.config.mjs

@@ -0,0 +1,36 @@
+import globals from "globals";
+import yoastConfig from "eslint-config-yoast";
+
+/** @type {import('eslint').Linter.Config[]} */
+export default [
+	...yoastConfig,
+	{
+		languageOptions: {
+			ecmaVersion: "latest",
+			globals: {
+				...globals.node,
+			},
+		},
+		rules: {
+			// Deviate from the Yoast config to prohibit dangling commas in functions.
+			"stylistic/comma-dangle": [
+				"error",
+				{
+					functions: "never",
+					arrays: "always-multiline",
+					objects: "always-multiline",
+					imports: "always-multiline",
+					exports: "always-multiline",
+				},
+			],
+		},
+	},
+	{
+		files: [ "*.config.*" ],
+		languageOptions: {
+			globals: {
+				...globals.node,
+			},
+		},
+	},
+];

packages/browserslist-config/package.json

@@ -27,6 +27,9 @@
   },
   "devDependencies": {
     "browserslist": "^4.7.3",
+    "eslint": "^9.16.0",
+    "eslint-config-yoast": "^6.0.0",
+    "globals": "^15.13.0",
     "jest": "^29.7.0"
   }
 }

packages/components/eslint.config.mjs

@@ -0,0 +1,55 @@
+import globals from "globals";
+import yoastConfig, { reactConfig } from "eslint-config-yoast";
+
+/** @type {import('eslint').Linter.Config[]} */
+export default [
+	{ ignores: [ "build" ] },
+	...yoastConfig,
+	...reactConfig,
+	{
+		languageOptions: {
+			ecmaVersion: "latest",
+			globals: {
+				...globals.browser,
+			},
+		},
+		rules: {
+			// Account for webpack externals and potentially unbuilt packages in the monorepo setup.
+			"import/no-unresolved": [
+				"error",
+				{
+					ignore: [
+						// Ignore @yoast packages from this workspace, or we have to build the code before linting.
+						// Because `main` in `package.json` points to the `build/index.js`, which is not present before building.
+						// As we are dealing with our source, not the actual NPM download, due to the monorepo setup.
+						"^@yoast/(ui-library|style-guide|components|helpers|search-metadata-previews|social-metadata-forms|replacement-variable-editor|analysis-report|feature-flag|related-keyphrase-suggestions)$",
+						"yoastseo",
+					],
+				},
+			],
+
+			// Deviate from the Yoast config to prohibit dangling commas in functions.
+			"stylistic/comma-dangle": [
+				"error",
+				{
+					functions: "never",
+					arrays: "always-multiline",
+					objects: "always-multiline",
+					imports: "always-multiline",
+					exports: "always-multiline",
+				},
+			],
+
+			// Deviate from the Yoast config to allow existing violations. New occurrences are still disallowed.
+			"react/jsx-no-bind": "warn",
+		},
+	},
+	{
+		files: [ "*.config.*", "jest/**" ],
+		languageOptions: {
+			globals: {
+				...globals.node,
+			},
+		},
+	},
+];

packages/components/package.json

@@ -21,7 +21,7 @@
     "build:css": "postcss src/**/*.css --base src --dir build",
     "clean": "rm -rf build",
     "test": "jest",
-    "lint": "eslint . --max-warnings=0"
+    "lint": "eslint . --max-warnings=20"
   },
   "dependencies": {
     "@wordpress/a11y": "^1.1.3",
@@ -48,6 +48,9 @@
     "babel-plugin-styled-components": "^2.0.6",
     "browserslist": "^4.7.3",
     "cssnano": "^6.0.2",
+    "eslint": "^9.16.0",
+    "eslint-config-yoast": "^6.0.0",
+    "globals": "^15.13.0",
     "jest": "^27.5.1",
     "jest-styled-components": "^7.0.3",
     "postcss": "^8.4.32",