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qwen/nodejs/node_modules/eslint/lib/rules/no-self-compare.js

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+/**
+ * @fileoverview Rule to flag comparison where left part is the same as the right
+ * part.
+ * @author Ilya Volodin
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('../shared/types').Rule} */
+module.exports = {
+    meta: {
+        type: "problem",
+
+        docs: {
+            description: "Disallow comparisons where both sides are exactly the same",
+            recommended: false,
+            url: "https://eslint.org/docs/latest/rules/no-self-compare"
+        },
+
+        schema: [],
+
+        messages: {
+            comparingToSelf: "Comparing to itself is potentially pointless."
+        }
+    },
+
+    create(context) {
+        const sourceCode = context.sourceCode;
+
+        /**
+         * Determines whether two nodes are composed of the same tokens.
+         * @param {ASTNode} nodeA The first node
+         * @param {ASTNode} nodeB The second node
+         * @returns {boolean} true if the nodes have identical token representations
+         */
+        function hasSameTokens(nodeA, nodeB) {
+            const tokensA = sourceCode.getTokens(nodeA);
+            const tokensB = sourceCode.getTokens(nodeB);
+
+            return tokensA.length === tokensB.length &&
+                tokensA.every((token, index) => token.type === tokensB[index].type && token.value === tokensB[index].value);
+        }
+
+        return {
+
+            BinaryExpression(node) {
+                const operators = new Set(["===", "==", "!==", "!=", ">", "<", ">=", "<="]);
+
+                if (operators.has(node.operator) && hasSameTokens(node.left, node.right)) {
+                    context.report({ node, messageId: "comparingToSelf" });
+                }
+            }
+        };
+
+    }
+};