feat: move to eslint flat config (#244)

* feat: move to eslint flat config

Co-authored-by: Joe Harvey <jdharvey-ibm@users.noreply.github.com>

eslint.config.js

@@ -0,0 +1,208 @@
+/*
+ * Copyright IBM Corp. 2024, 2024
+ *
+ * This source code is licensed under the Apache-2.0 license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import eslintComments from '@eslint-community/eslint-plugin-eslint-comments/configs'
+import jsdoc from 'eslint-plugin-jsdoc'
+import n from 'eslint-plugin-n'
+import notice from 'eslint-plugin-notice'
+import simpleImportSort from 'eslint-plugin-simple-import-sort'
+import vitest from 'eslint-plugin-vitest'
+import globals from 'globals'
+import tsEslint from 'typescript-eslint'
+
+const noUnusedVarsOptions = { args: 'all', argsIgnorePattern: '^_', varsIgnorePattern: '^_' }
+
+const files = ['**/*.{js,cjs,mjs,jsx,ts,tsx}']
+
+const config = [
+  {
+    ignores: [
+      '**/.history/*',
+      '**/.vscode/*',
+      '**/.test-coverage/*',
+      '**/dist/*',
+      'src/test/__fixtures/*',
+      '.copyright.js'
+    ]
+  },
+  ...tsEslint.configs.strict.map((config) => ({
+    ...config,
+    files,
+    languageOptions: {
+      parser: tsEslint.parser,
+      parserOptions: {
+        project: 'tsconfig.eslint.json'
+      }
+    }
+  })),
+  {
+    ...eslintComments.recommended,
+    files
+  },
+  {
+    ...jsdoc.configs['flat/recommended-typescript'],
+    files
+  },
+  {
+    ...n.configs['flat/recommended'],
+    files
+  },
+  {
+    //
+    // Default config for all files
+    //
+    files: files,
+    languageOptions: {
+      ecmaVersion: 'latest',
+      sourceType: 'module',
+      globals: {
+        ...globals.es2021,
+        ...globals.node
+      }
+    },
+    plugins: {
+      notice,
+      'simple-import-sort': simpleImportSort
+    },
+    rules: {
+      '@typescript-eslint/consistent-type-imports': 'error',
+      '@typescript-eslint/explicit-function-return-type': 'off',
+      '@typescript-eslint/no-explicit-any': 'warn',
+      '@typescript-eslint/no-extraneous-class': [
+        'error',
+        {
+          allowWithDecorator: true
+        }
+      ],
+      '@typescript-eslint/no-unused-vars': ['warn', noUnusedVarsOptions],
+      '@typescript-eslint/space-before-function-paren': [
+        'warn',
+        {
+          anonymous: 'always',
+          named: 'never',
+          asyncArrow: 'always'
+        }
+      ],
+      '@typescript-eslint/strict-boolean-expressions': [
+        'warn',
+        {
+          allowString: false,
+          allowNumber: false,
+          allowNullableObject: true,
+          allowNullableBoolean: true,
+          allowNullableString: false,
+          allowNullableNumber: false,
+          allowNullableEnum: false,
+          allowAny: false
+        }
+      ],
+      '@eslint-community/eslint-comments/require-description': 'warn',
+      indent: [
+        'warn',
+        2,
+        {
+          ignoredNodes: [
+            'PropertyDefinition[decorators]',
+            'VariableDeclaration[declarations.length=0]'
+          ],
+          SwitchCase: 1
+        }
+      ],
+      'jsdoc/check-tag-names': 'off', // To support JSON schema file generation based on TypeScript
+      'jsdoc/require-description': [
+        'warn',
+        {
+          contexts: [
+            'ClassDeclaration',
+            'FunctionDeclaration',
+            'MethodDefinition',
+            'PropertyDefinition',
+            'TSAbstractMethodDefinition'
+          ]
+        }
+      ],
+      'jsdoc/require-description-complete-sentence': 'warn',
+      'jsdoc/require-hyphen-before-param-description': 'warn',
+      'jsdoc/require-jsdoc': [
+        'warn',
+        {
+          // publicOnly: true,
+          require: {
+            //   ArrowFunctionExpression: true,
+            // ClassDeclaration: true,
+            //   ClassExpression: false,
+            FunctionDeclaration: false
+            //   FunctionExpression: false,
+            //   MethodDefinition: true
+          },
+          contexts: [
+            'ClassDeclaration',
+            'ExportNamedDeclaration > FunctionDeclaration',
+            'MethodDefinition[accessibility="protected"][override=false]',
+            'MethodDefinition[accessibility="public"][override=false]',
+            'TSAbstractMethodDefinition[accessibility="public"]',
+            'TSAbstractMethodDefinition[accessibility="protected"]'
+          ]
+        }
+      ],
+      'jsdoc/require-param-description': 'warn',
+      'jsdoc/require-throws': 'warn',
+      'jsdoc/tag-lines': [
+        'warn',
+        'any',
+        {
+          startLines: 1,
+          endLines: 0,
+          tags: { param: { lines: 'never' }, returns: { lines: 'never' } }
+        }
+      ],
+      'max-len': [
+        'warn',
+        {
+          code: 150, // Effectively disable this rule and allow Prettier to handle it
+          comments: 100
+        }
+      ],
+      'n/no-unpublished-import': ['error', { allowModules: ['vitest'] }],
+      'n/shebang': 'off',
+      'notice/notice': ['warn', { templateFile: './.copyright.js' }],
+      'simple-import-sort/imports': 'warn',
+      'simple-import-sort/exports': 'warn'
+    }
+  },
+  {
+    //
+    // Special rules for config files
+    //
+    files: ['.*rc.{js,cjs}', '*.config.js'],
+    languageOptions: {
+      globals: {
+        ...globals.node
+      }
+    },
+    rules: {
+      'n/no-unpublished-import': 'off'
+    }
+  },
+  {
+    //
+    // Special rules for test files
+    //
+    ...vitest.configs.all,
+    files: ['**/*.test.ts'],
+    plugins: {
+      vitest
+    },
+    rules: {
+      'n/no-unpublished-import': 'off',
+      'vitest/no-hooks': 'off',
+      'vitest/prefer-expect-assertions': 'off'
+    }
+  }
+]
+
+export default config