feat: simplify configs (#124)

BREAKING CHANGE: ES6, import & main configs don't have sub-configs anymore

README.md

@@ -102,24 +102,14 @@ for it.
 - All plugins needed for rules used by these configs are dependencies of this
   module so you don't have to install anything on your own.
 - The default config actually is composed of several configurations and you can
-  use those individually. These are the configs it's using:
-  `possible-errors.js`, `best-practices.js`, `stylistic.js`, `es6/index.js`, and
-  `import/index.js`. You can use each of these configs yourself if you want to
-  leave my own personal style out of it. Also, the `es6` and `import` configs
-  each have a `possible-errors.js`, `best-practices.js`, and `stylistic.js`
-  which they are composed of as well.
+  use those individually. You can use each of these configs yourself if you want
+  to leave my own personal style out of it.
 
-#### Example of highly customized config
+#### Example of customized config
 
 ```javascript
 module.exports = {
-  extends: [
-    'kentcdodds/possible-errors',
-    'kentcdodds/best-practices',
-    'kentcdodds/es6/possible-errors',
-    'kentcdodds/import',
-    'kentcdodds/jest',
-  ],
+  extends: ['kentcdodds/es6', 'kentcdodds/import', 'kentcdodds/jest'],
   rules: {
     /* custom rules */
   },

es6.js

@@ -0,0 +1,92 @@
+module.exports = {
+  env: {
+    es6: true,
+  },
+  extends: ['prettier'],
+  parser: '@babel/eslint-parser',
+  parserOptions: {
+    babelOptions: {
+      presets: ['@babel/preset-react'],
+    },
+    ecmaVersion: 2018,
+    requireConfigFile: false,
+    sourceType: 'module',
+  },
+  plugins: ['@babel'],
+  rules: {
+    'arrow-body-style': 'off',
+    'constructor-super': 'error',
+    'no-class-assign': 'error',
+    'no-const-assign': 'error',
+    'no-dupe-class-members': 'error',
+    'no-duplicate-imports': 'error',
+    'no-new-symbol': 'error',
+    'no-restricted-exports': 'off', // not applicable for a config preset (should be configured only in projects)
+    'no-restricted-imports': 'off', // not applicable for a config preset (should be configured only in projects)
+    'no-this-before-super': 'error',
+    'no-unsafe-optional-chaining': 'error',
+    'no-useless-computed-key': 'error',
+    'no-useless-constructor': 'error',
+    'no-useless-rename': 'error',
+    'no-var': 'error',
+    'object-shorthand': ['error', 'properties'], // methods are optional so you can specify a name if you want
+    'prefer-arrow-callback': [
+      'error',
+      {allowNamedFunctions: true, allowUnboundThis: true},
+    ],
+    'prefer-const': 'error',
+    'prefer-destructuring': 'off', // nah, I like it, but not that much...
+    'prefer-numeric-literals': 'error',
+    'prefer-rest-params': 'error',
+    'prefer-spread': 'error',
+    'prefer-template': 'error',
+    'require-yield': 'error',
+    'sort-imports': 'off',
+    'symbol-description': 'error',
+
+    'new-cap': 'off',
+    '@babel/new-cap': ['error', {capIsNew: true, newIsCap: true}],
+
+    'no-invalid-this': 'off',
+    '@babel/no-invalid-this': 'error',
+
+    'no-unused-expressions': 'off',
+    '@babel/no-unused-expressions': 'error',
+  },
+  overrides: [
+    {
+      files: ['**/*.ts?(x)'],
+      parser: '@typescript-eslint/parser',
+      parserOptions: {
+        ecmaVersion: 2018,
+        sourceType: 'module',
+      },
+      plugins: ['@typescript-eslint'],
+      rules: {
+        'constructor-super': 'off', // ts(2335) & ts(2377)
+        'no-const-assign': 'off', // ts(2588)
+        'no-new-symbol': 'off', // ts(2588)
+        'no-this-before-super': 'off', // ts(2376)
+        'no-var': 'error', // ts transpiles let/const to var, so no need for vars any more
+        'prefer-const': 'error', // ts provides better types with const
+        'prefer-rest-params': 'error', // ts provides better types with rest args over arguments
+        'prefer-spread': 'error', // ts transpiles spread to apply, so no need for manual apply
+
+        'no-dupe-class-members': 'off',
+        '@typescript-eslint/no-dupe-class-members': 'off', // ts(2393) & ts(2300)
+
+        'no-duplicate-imports': 'off',
+        '@typescript-eslint/no-duplicate-imports': 'error',
+
+        'no-useless-constructor': 'off',
+        '@typescript-eslint/no-useless-constructor': 'error',
+
+        '@babel/no-invalid-this': 'off',
+        '@typescript-eslint/no-invalid-this': 'error',
+
+        '@babel/no-unused-expressions': 'off',
+        '@typescript-eslint/no-unused-expressions': 'error',
+      },
+    },
+  ],
+}