Improve requireMultipleVarDecl rule

Do not treat var and const statements as same entity

Fixes #462

Author: markelog

lib/rules/require-multiple-var-decl.js

@@ -5,9 +5,9 @@ function consecutive(file, errors) {
         var pos = node.parentCollection.indexOf(node);
         if (pos < node.parentCollection.length - 1) {
             var sibling = node.parentCollection[pos + 1];
-            if (sibling.type === 'VariableDeclaration') {
+            if (sibling.type === 'VariableDeclaration' && sibling.kind === node.kind) {
                 errors.add(
-                    'Var declarations should be joined',
+                    node.kind[0].toUpperCase() + node.kind.slice(1) + ' declarations should be joined',
                     sibling.loc.start
                 );
             }
@@ -18,10 +18,12 @@ function consecutive(file, errors) {
 function onevar(file, errors) {
     file.iterateNodesByType(['Program', 'FunctionDeclaration', 'FunctionExpression'], function(node) {
         var firstVar = true;
+        var firstConst = true;
         var firstParent = true;
 
         file.iterate(function(node) {
             var type = node && node.type;
+            var kind = node && node.kind;
 
             // Don't go in nested scopes
             if (!firstParent && type && ['FunctionDeclaration', 'FunctionExpression'].indexOf(type) > -1) {
@@ -33,13 +35,26 @@ function onevar(file, errors) {
             }
 
             if (type === 'VariableDeclaration') {
-                if (!firstVar) {
-                    errors.add(
-                        'Var declarations should be joined',
-                        node.loc.start
-                    );
-                } else {
-                    firstVar = false;
+                if (kind === 'var') {
+                    if (!firstVar) {
+                        errors.add(
+                            'Var declarations should be joined',
+                            node.loc.start
+                        );
+                    } else {
+                        firstVar = false;
+                    }
+                }
+
+                if (kind === 'const') {
+                    if (!firstConst) {
+                        errors.add(
+                            'Const declarations should be joined',
+                            node.loc.start
+                        );
+                    } else {
+                        firstConst = false;
+                    }
                 }
             }
         }, node);

test/rules/require-multiple-var-decl.js

@@ -14,6 +14,9 @@ describe('rules/require-multiple-var-decl', function() {
             checker.registerDefaultRules();
             checker.configure({ requireMultipleVarDecl: true });
         });
+        it('should not report const and var decls as one entity (#462)', function() {
+            assert(checker.checkString('const a = 1; var b = 2;').isEmpty());
+        });
         it('should report consecutive var decl', function() {
             assert(checker.checkString('var x; var y;').getErrorCount() === 1);
         });
@@ -32,6 +35,9 @@ describe('rules/require-multiple-var-decl', function() {
             checker.configure({ requireMultipleVarDecl: 'onevar' });
         });
 
+        it('should not report const and var decls as one entity (#462)', function() {
+            assert(checker.checkString('const a = 1; var b = 2;').isEmpty());
+        });
         it('should report consecutive var decl', function() {
             assert(checker.checkString('var x; var y;').getErrorCount() === 1);
         });
@@ -51,6 +57,30 @@ describe('rules/require-multiple-var-decl', function() {
             }
             assert(checker.checkString(test.toString()).getErrorCount() === 1);
         });
+        it('should report multiple const in function', function() {
+            /* jshint esnext: true */
+            function test() {
+                const first = true;
+
+                if (true) {
+                    const second = 2;
+                }
+            }
+            assert(checker.checkString(test.toString()).getErrorCount() === 1);
+        });
+        it('should report multiple const and vars in function', function() {
+            /* jshint esnext: true */
+            function test() {
+                const firstConst = true;
+                var firstVar = true;
+
+                if (true) {
+                    const secondConst = 2;
+                    var secondVar = 2;
+                }
+            }
+            assert(checker.checkString(test.toString()).getErrorCount() === 2);
+        });
         it('should not confuse two separate functions', function() {
             function testFunc() {
                 function foo() {