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qwen/nodejs/node_modules/eslint/lib/rules/block-scoped-var.js

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+/**
+ * @fileoverview Rule to check for "block scoped" variables by binding context
+ * @author Matt DuVall <http://www.mattduvall.com>
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('../shared/types').Rule} */
+module.exports = {
+    meta: {
+        type: "suggestion",
+
+        docs: {
+            description: "Enforce the use of variables within the scope they are defined",
+            recommended: false,
+            url: "https://eslint.org/docs/latest/rules/block-scoped-var"
+        },
+
+        schema: [],
+
+        messages: {
+            outOfScope: "'{{name}}' declared on line {{definitionLine}} column {{definitionColumn}} is used outside of binding context."
+        }
+    },
+
+    create(context) {
+        let stack = [];
+        const sourceCode = context.sourceCode;
+
+        /**
+         * Makes a block scope.
+         * @param {ASTNode} node A node of a scope.
+         * @returns {void}
+         */
+        function enterScope(node) {
+            stack.push(node.range);
+        }
+
+        /**
+         * Pops the last block scope.
+         * @returns {void}
+         */
+        function exitScope() {
+            stack.pop();
+        }
+
+        /**
+         * Reports a given reference.
+         * @param {eslint-scope.Reference} reference A reference to report.
+         * @param {eslint-scope.Definition} definition A definition for which to report reference.
+         * @returns {void}
+         */
+        function report(reference, definition) {
+            const identifier = reference.identifier;
+            const definitionPosition = definition.name.loc.start;
+
+            context.report({
+                node: identifier,
+                messageId: "outOfScope",
+                data: {
+                    name: identifier.name,
+                    definitionLine: definitionPosition.line,
+                    definitionColumn: definitionPosition.column + 1
+                }
+            });
+        }
+
+        /**
+         * Finds and reports references which are outside of valid scopes.
+         * @param {ASTNode} node A node to get variables.
+         * @returns {void}
+         */
+        function checkForVariables(node) {
+            if (node.kind !== "var") {
+                return;
+            }
+
+            // Defines a predicate to check whether or not a given reference is outside of valid scope.
+            const scopeRange = stack[stack.length - 1];
+
+            /**
+             * Check if a reference is out of scope
+             * @param {ASTNode} reference node to examine
+             * @returns {boolean} True is its outside the scope
+             * @private
+             */
+            function isOutsideOfScope(reference) {
+                const idRange = reference.identifier.range;
+
+                return idRange[0] < scopeRange[0] || idRange[1] > scopeRange[1];
+            }
+
+            // Gets declared variables, and checks its references.
+            const variables = sourceCode.getDeclaredVariables(node);
+
+            for (let i = 0; i < variables.length; ++i) {
+
+                // Reports.
+                variables[i]
+                    .references
+                    .filter(isOutsideOfScope)
+                    .forEach(ref => report(ref, variables[i].defs.find(def => def.parent === node)));
+            }
+        }
+
+        return {
+            Program(node) {
+                stack = [node.range];
+            },
+
+            // Manages scopes.
+            BlockStatement: enterScope,
+            "BlockStatement:exit": exitScope,
+            ForStatement: enterScope,
+            "ForStatement:exit": exitScope,
+            ForInStatement: enterScope,
+            "ForInStatement:exit": exitScope,
+            ForOfStatement: enterScope,
+            "ForOfStatement:exit": exitScope,
+            SwitchStatement: enterScope,
+            "SwitchStatement:exit": exitScope,
+            CatchClause: enterScope,
+            "CatchClause:exit": exitScope,
+            StaticBlock: enterScope,
+            "StaticBlock:exit": exitScope,
+
+            // Finds and reports references which are outside of valid scope.
+            VariableDeclaration: checkForVariables
+        };
+
+    }
+};