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qwen/nodejs/node_modules/eslint/lib/rules/no-undef.js

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+/**
+ * @fileoverview Rule to flag references to undeclared variables.
+ * @author Mark Macdonald
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Checks if the given node is the argument of a typeof operator.
+ * @param {ASTNode} node The AST node being checked.
+ * @returns {boolean} Whether or not the node is the argument of a typeof operator.
+ */
+function hasTypeOfOperator(node) {
+    const parent = node.parent;
+
+    return parent.type === "UnaryExpression" && parent.operator === "typeof";
+}
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('../shared/types').Rule} */
+module.exports = {
+    meta: {
+        type: "problem",
+
+        docs: {
+            description: "Disallow the use of undeclared variables unless mentioned in `/*global */` comments",
+            recommended: true,
+            url: "https://eslint.org/docs/latest/rules/no-undef"
+        },
+
+        schema: [
+            {
+                type: "object",
+                properties: {
+                    typeof: {
+                        type: "boolean",
+                        default: false
+                    }
+                },
+                additionalProperties: false
+            }
+        ],
+        messages: {
+            undef: "'{{name}}' is not defined."
+        }
+    },
+
+    create(context) {
+        const options = context.options[0];
+        const considerTypeOf = options && options.typeof === true || false;
+        const sourceCode = context.sourceCode;
+
+        return {
+            "Program:exit"(node) {
+                const globalScope = sourceCode.getScope(node);
+
+                globalScope.through.forEach(ref => {
+                    const identifier = ref.identifier;
+
+                    if (!considerTypeOf && hasTypeOfOperator(identifier)) {
+                        return;
+                    }
+
+                    context.report({
+                        node: identifier,
+                        messageId: "undef",
+                        data: identifier
+                    });
+                });
+            }
+        };
+    }
+};