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qwen/nodejs/node_modules/eslint/lib/rules/no-lonely-if.js

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+/**
+ * @fileoverview Rule to disallow if as the only statement in an else block
+ * @author Brandon Mills
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('../shared/types').Rule} */
+module.exports = {
+    meta: {
+        type: "suggestion",
+
+        docs: {
+            description: "Disallow `if` statements as the only statement in `else` blocks",
+            recommended: false,
+            url: "https://eslint.org/docs/latest/rules/no-lonely-if"
+        },
+
+        schema: [],
+        fixable: "code",
+
+        messages: {
+            unexpectedLonelyIf: "Unexpected if as the only statement in an else block."
+        }
+    },
+
+    create(context) {
+        const sourceCode = context.sourceCode;
+
+        return {
+            IfStatement(node) {
+                const parent = node.parent,
+                    grandparent = parent.parent;
+
+                if (parent && parent.type === "BlockStatement" &&
+                        parent.body.length === 1 && grandparent &&
+                        grandparent.type === "IfStatement" &&
+                        parent === grandparent.alternate) {
+                    context.report({
+                        node,
+                        messageId: "unexpectedLonelyIf",
+                        fix(fixer) {
+                            const openingElseCurly = sourceCode.getFirstToken(parent);
+                            const closingElseCurly = sourceCode.getLastToken(parent);
+                            const elseKeyword = sourceCode.getTokenBefore(openingElseCurly);
+                            const tokenAfterElseBlock = sourceCode.getTokenAfter(closingElseCurly);
+                            const lastIfToken = sourceCode.getLastToken(node.consequent);
+                            const sourceText = sourceCode.getText();
+
+                            if (sourceText.slice(openingElseCurly.range[1],
+                                node.range[0]).trim() || sourceText.slice(node.range[1], closingElseCurly.range[0]).trim()) {
+
+                                // Don't fix if there are any non-whitespace characters interfering (e.g. comments)
+                                return null;
+                            }
+
+                            if (
+                                node.consequent.type !== "BlockStatement" && lastIfToken.value !== ";" && tokenAfterElseBlock &&
+                                (
+                                    node.consequent.loc.end.line === tokenAfterElseBlock.loc.start.line ||
+                                    /^[([/+`-]/u.test(tokenAfterElseBlock.value) ||
+                                    lastIfToken.value === "++" ||
+                                    lastIfToken.value === "--"
+                                )
+                            ) {
+
+                                /*
+                                 * If the `if` statement has no block, and is not followed by a semicolon, make sure that fixing
+                                 * the issue would not change semantics due to ASI. If this would happen, don't do a fix.
+                                 */
+                                return null;
+                            }
+
+                            return fixer.replaceTextRange(
+                                [openingElseCurly.range[0], closingElseCurly.range[1]],
+                                (elseKeyword.range[1] === openingElseCurly.range[0] ? " " : "") + sourceCode.getText(node)
+                            );
+                        }
+                    });
+                }
+            }
+        };
+
+    }
+};