1 files changed, 112 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/no-lone-blocks.js b/tools/node_modules/eslint/lib/rules/no-lone-blocks.js
new file mode 100644
index 0000000000..2b5666e213
--- /dev/null
+++ b/tools/node_modules/eslint/lib/rules/no-lone-blocks.js
@@ -0,0 +1,112 @@
+/**
+ * @fileoverview Rule to flag blocks with no reason to exist
+ * @author Brandon Mills
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow unnecessary nested blocks",
+            category: "Best Practices",
+            recommended: false
+        },
+
+        schema: []
+    },
+
+    create(context) {
+
+        // A stack of lone blocks to be checked for block-level bindings
+        const loneBlocks = [];
+        let ruleDef;
+
+        /**
+         * Reports a node as invalid.
+         * @param {ASTNode} node - The node to be reported.
+         * @returns {void}
+         */
+        function report(node) {
+            const message = node.parent.type === "BlockStatement" ? "Nested block is redundant." : "Block is redundant.";
+
+            context.report({ node, message });
+        }
+
+        /**
+         * Checks for any ocurrence of a BlockStatement in a place where lists of statements can appear
+         * @param {ASTNode} node The node to check
+         * @returns {boolean} True if the node is a lone block.
+         */
+        function isLoneBlock(node) {
+            return node.parent.type === "BlockStatement" ||
+                node.parent.type === "Program" ||
+
+                // Don't report blocks in switch cases if the block is the only statement of the case.
+                node.parent.type === "SwitchCase" && !(node.parent.consequent[0] === node && node.parent.consequent.length === 1);
+        }
+
+        /**
+         * Checks the enclosing block of the current node for block-level bindings,
+         * and "marks it" as valid if any.
+         * @returns {void}
+         */
+        function markLoneBlock() {
+            if (loneBlocks.length === 0) {
+                return;
+            }
+
+            const block = context.getAncestors().pop();
+
+            if (loneBlocks[loneBlocks.length - 1] === block) {
+                loneBlocks.pop();
+            }
+        }
+
+        // Default rule definition: report all lone blocks
+        ruleDef = {
+            BlockStatement(node) {
+                if (isLoneBlock(node)) {
+                    report(node);
+                }
+            }
+        };
+
+        // ES6: report blocks without block-level bindings
+        if (context.parserOptions.ecmaVersion >= 6) {
+            ruleDef = {
+                BlockStatement(node) {
+                    if (isLoneBlock(node)) {
+                        loneBlocks.push(node);
+                    }
+                },
+                "BlockStatement:exit"(node) {
+                    if (loneBlocks.length > 0 && loneBlocks[loneBlocks.length - 1] === node) {
+                        loneBlocks.pop();
+                        report(node);
+                    }
+                }
+            };
+
+            ruleDef.VariableDeclaration = function(node) {
+                if (node.kind === "let" || node.kind === "const") {
+                    markLoneBlock();
+                }
+            };
+
+            ruleDef.FunctionDeclaration = function() {
+                if (context.getScope().isStrict) {
+                    markLoneBlock();
+                }
+            };
+
+            ruleDef.ClassDeclaration = markLoneBlock;
+        }
+
+        return ruleDef;
+    }
+};