feat(rules): add variables rule set

index.js

@@ -1,5 +1,6 @@
 module.exports = {
   extends: [
+    './rules/variables',
     './rules/node',
     './rules/stylistic-issues',
     './rules/es2015'

rules/variables.js

@@ -0,0 +1,51 @@
+module.exports = {
+  rules: {
+    // require or disallow initialization in variable declarations
+    // http://eslint.org/docs/rules/init-declarations
+    'init-declarations': 'off',
+
+    // disallow catch clause parameters from shadowing variables in the outer scope
+    // http://eslint.org/docs/rules/no-catch-shadow
+    'no-catch-shadow': 'off',
+
+    // disallow deleting variables
+    // http://eslint.org/docs/rules/no-delete-var
+    'no-delete-var': 'error',
+
+    // disallow labels that share a name with a variable
+    // http://eslint.org/docs/rules/no-label-var
+    'no-label-var': 'error',
+
+    // disallow specified global variables
+    // http://eslint.org/docs/rules/no-restricted-globals
+    'no-restricted-globals': 'off',
+
+    // disallow identifiers from shadowing restricted names
+    // http://eslint.org/docs/rules/no-shadow-restricted-names
+    'no-shadow-restricted-names': 'error',
+
+    // disallow variable declarations from shadowing variables declared in the outer scope
+    // http://eslint.org/docs/rules/no-shadow
+    'no-shadow': 'error',
+
+    // disallow initializing variables to undefined
+    // http://eslint.org/docs/rules/no-undef-init
+    'no-undef-init': 'error',
+
+    // disallow the use of undeclared variables unless mentioned in /*global */ comments
+    // http://eslint.org/docs/rules/no-undef
+    'no-undef': 'error',
+
+    // disallow the use of undefined as an identifier
+    // http://eslint.org/docs/rules/no-undefined
+    'no-undefined': 'on',
+
+    // disallow unused variables
+    // http://eslint.org/docs/rules/no-unused-vars
+    'no-unused-vars': ['error', { vars: 'local', args: 'after-used' }],
+
+    // disallow the use of variables before they are defined
+    // http://eslint.org/docs/rules/no-use-before-define
+    'no-use-before-define': 'error'
+  }
+};