.

qwen/nodejs/node_modules/eslint/lib/rules/no-extra-label.js

@@ -0,0 +1,149 @@
+/**
+ * @fileoverview Rule to disallow unnecessary labels
+ * @author Toru Nagashima
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("./utils/ast-utils");
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('../shared/types').Rule} */
+module.exports = {
+    meta: {
+        type: "suggestion",
+
+        docs: {
+            description: "Disallow unnecessary labels",
+            recommended: false,
+            url: "https://eslint.org/docs/latest/rules/no-extra-label"
+        },
+
+        schema: [],
+        fixable: "code",
+
+        messages: {
+            unexpected: "This label '{{name}}' is unnecessary."
+        }
+    },
+
+    create(context) {
+        const sourceCode = context.sourceCode;
+        let scopeInfo = null;
+
+        /**
+         * Creates a new scope with a breakable statement.
+         * @param {ASTNode} node A node to create. This is a BreakableStatement.
+         * @returns {void}
+         */
+        function enterBreakableStatement(node) {
+            scopeInfo = {
+                label: node.parent.type === "LabeledStatement" ? node.parent.label : null,
+                breakable: true,
+                upper: scopeInfo
+            };
+        }
+
+        /**
+         * Removes the top scope of the stack.
+         * @returns {void}
+         */
+        function exitBreakableStatement() {
+            scopeInfo = scopeInfo.upper;
+        }
+
+        /**
+         * Creates a new scope with a labeled statement.
+         *
+         * This ignores it if the body is a breakable statement.
+         * In this case it's handled in the `enterBreakableStatement` function.
+         * @param {ASTNode} node A node to create. This is a LabeledStatement.
+         * @returns {void}
+         */
+        function enterLabeledStatement(node) {
+            if (!astUtils.isBreakableStatement(node.body)) {
+                scopeInfo = {
+                    label: node.label,
+                    breakable: false,
+                    upper: scopeInfo
+                };
+            }
+        }
+
+        /**
+         * Removes the top scope of the stack.
+         *
+         * This ignores it if the body is a breakable statement.
+         * In this case it's handled in the `exitBreakableStatement` function.
+         * @param {ASTNode} node A node. This is a LabeledStatement.
+         * @returns {void}
+         */
+        function exitLabeledStatement(node) {
+            if (!astUtils.isBreakableStatement(node.body)) {
+                scopeInfo = scopeInfo.upper;
+            }
+        }
+
+        /**
+         * Reports a given control node if it's unnecessary.
+         * @param {ASTNode} node A node. This is a BreakStatement or a
+         *      ContinueStatement.
+         * @returns {void}
+         */
+        function reportIfUnnecessary(node) {
+            if (!node.label) {
+                return;
+            }
+
+            const labelNode = node.label;
+
+            for (let info = scopeInfo; info !== null; info = info.upper) {
+                if (info.breakable || info.label && info.label.name === labelNode.name) {
+                    if (info.breakable && info.label && info.label.name === labelNode.name) {
+                        context.report({
+                            node: labelNode,
+                            messageId: "unexpected",
+                            data: labelNode,
+                            fix(fixer) {
+                                const breakOrContinueToken = sourceCode.getFirstToken(node);
+
+                                if (sourceCode.commentsExistBetween(breakOrContinueToken, labelNode)) {
+                                    return null;
+                                }
+
+                                return fixer.removeRange([breakOrContinueToken.range[1], labelNode.range[1]]);
+                            }
+                        });
+                    }
+                    return;
+                }
+            }
+        }
+
+        return {
+            WhileStatement: enterBreakableStatement,
+            "WhileStatement:exit": exitBreakableStatement,
+            DoWhileStatement: enterBreakableStatement,
+            "DoWhileStatement:exit": exitBreakableStatement,
+            ForStatement: enterBreakableStatement,
+            "ForStatement:exit": exitBreakableStatement,
+            ForInStatement: enterBreakableStatement,
+            "ForInStatement:exit": exitBreakableStatement,
+            ForOfStatement: enterBreakableStatement,
+            "ForOfStatement:exit": exitBreakableStatement,
+            SwitchStatement: enterBreakableStatement,
+            "SwitchStatement:exit": exitBreakableStatement,
+            LabeledStatement: enterLabeledStatement,
+            "LabeledStatement:exit": exitLabeledStatement,
+            BreakStatement: reportIfUnnecessary,
+            ContinueStatement: reportIfUnnecessary
+        };
+    }
+};