chore: Update to eslint 9

Author: XM5jDcsHTyGJtQqlCi

.eslintignore

@@ -0,0 +1,82 @@
+import js from '@eslint/js';
+import eslintConfigPrettier from 'eslint-config-prettier';
+import globals from 'globals';
+
+import tseslint from 'typescript-eslint';
+
+export default [
+  {
+    ignores: [
+      '**/dist/',
+      '**/node_modules/',
+      '**/package.json',
+      '**/package-lock.json',
+      'coverage/',
+      'docs/',
+      'mf1/examples/cli/*.mjs',
+      'mf1/examples/react/',
+      'mf1/packages/core/lib/*',
+      'mf1/packages/core/messageformat.*',
+      'mf1/packages/date-skeleton/lib/*',
+      'mf1/packages/number-skeleton/lib/*',
+      'mf1/packages/parser/lib/*',
+      'mf1/packages/react/lib/*',
+      'mf1/packages/react/src/__fixtures__/*',
+      'mf1/packages/rollup-plugin/lib/*',
+      'mf1/packages/runtime/esm/*',
+      'mf1/packages/runtime/lib/*',
+      'mf2/*/lib/*',
+      'test/messageformat-wg/',
+      'tmp/'
+    ]
+  },
+  js.configs.recommended,
+  ...tseslint.configs.recommended,
+  eslintConfigPrettier,
+  {
+    languageOptions: {
+      globals: { ...globals.node },
+      ecmaVersion: 2018,
+      sourceType: 'module'
+    },
+
+    rules: {
+      'array-callback-return': 'error',
+      camelcase: 'off',
+      'consistent-return': 'error',
+      curly: ['warn', 'multi-line', 'consistent'],
+      eqeqeq: ['error', 'smart'],
+      'no-constant-condition': ['error', { checkLoops: false }],
+      'no-implicit-globals': 'error',
+      'no-useless-rename': 'error',
+      'prefer-const': ['error', { destructuring: 'all' }],
+      'sort-imports': ['warn', { ignoreDeclarationSort: true }]
+    }
+  },
+  {
+    files: ['**/*.js'],
+    rules: {
+      'no-unused-vars': ['warn', { argsIgnorePattern: '^_' }],
+      '@typescript-eslint/no-require-imports': 'off'
+    }
+  },
+  {
+    files: ['**/*.{ts,tsx}'],
+    rules: {
+      'no-unused-vars': 'off',
+      '@typescript-eslint/explicit-module-boundary-types': 'off',
+      '@typescript-eslint/no-unused-vars': ['warn', { argsIgnorePattern: '^_' }]
+    }
+  },
+  {
+    files: ['test/browser/tests/*.js'],
+    languageOptions: { globals: { ...globals.mocha } }
+  },
+  {
+    files: ['**/*.test.{mts,ts,tsx}', 'test/**/*.ts'],
+    rules: {
+      '@typescript-eslint/ban-ts-comment': 'off',
+      '@typescript-eslint/no-explicit-any': 'off'
+    }
+  }
+];

.eslintrc.yaml

@@ -1,4 +1,4 @@
-/* eslint-env browser */
+/* global document */
 
 import messages from './messages.yaml';
 

eslint.config.mjs

@@ -20,7 +20,7 @@ module.exports = function getOptions() {
         cfg = YAML.parse(src);
       }
       break;
-    } catch (e) {
+    } catch {
       /* ignore errors */
     }
   }

mf1/examples/webpack/src/index.js

@@ -222,8 +222,6 @@ const tests: { [K in keyof Skeleton]: { [name: string]: TestCase } } = {
     },
     'sign-except-zero': {
       skeleton: { sign: 'sign-except-zero' },
-      // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-      // @ts-ignore https://github.com/microsoft/TypeScript/issues/46712
       result: { signDisplay: 'exceptZero' }
     },
     'sign-never': {
@@ -240,8 +238,6 @@ const tests: { [K in keyof Skeleton]: { [name: string]: TestCase } } = {
     },
     'sign-accounting-except-zero': {
       skeleton: { sign: 'sign-accounting-except-zero' },
-      // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-      // @ts-ignore https://github.com/microsoft/TypeScript/issues/46712
       result: { currencySign: 'accounting', signDisplay: 'exceptZero' }
     }
   },

mf1/packages/cli/lib/options.js

@@ -1,4 +1,4 @@
-// eslint-disable-next-line @typescript-eslint/no-var-requires
+// eslint-disable-next-line @typescript-eslint/no-require-imports
 jest.mock('fs', () => require('memfs').fs);
 
 import { fs } from 'memfs';

mf1/packages/number-skeleton/src/numberformat/options.test.ts

@@ -29,7 +29,6 @@ export function time(
     minute: 'numeric',
     hour: 'numeric'
   };
-  /* eslint-disable no-fallthrough */
   switch (size) {
     case 'full':
     case 'long':

mf1/packages/rollup-plugin/src/index.test.ts

@@ -1,5 +1,3 @@
-/* eslint-disable @typescript-eslint/no-non-null-assertion */
-
 /**
  * The test cases included in this file have been extracted from the
  * @fluent/bundle 0.16.1 test files available at: