node_modules

node_modules/eslint/lib/rules/no-case-declarations.js

@@ -0,0 +1,64 @@
+/**
+ * @fileoverview Rule to flag use of an lexical declarations inside a case clause
+ * @author Erik Arvidsson
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        type: "suggestion",
+
+        docs: {
+            description: "disallow lexical declarations in case clauses",
+            category: "Best Practices",
+            recommended: true,
+            url: "https://eslint.org/docs/rules/no-case-declarations"
+        },
+
+        schema: [],
+
+        messages: {
+            unexpected: "Unexpected lexical declaration in case block."
+        }
+    },
+
+    create(context) {
+
+        /**
+         * Checks whether or not a node is a lexical declaration.
+         * @param {ASTNode} node A direct child statement of a switch case.
+         * @returns {boolean} Whether or not the node is a lexical declaration.
+         */
+        function isLexicalDeclaration(node) {
+            switch (node.type) {
+                case "FunctionDeclaration":
+                case "ClassDeclaration":
+                    return true;
+                case "VariableDeclaration":
+                    return node.kind !== "var";
+                default:
+                    return false;
+            }
+        }
+
+        return {
+            SwitchCase(node) {
+                for (let i = 0; i < node.consequent.length; i++) {
+                    const statement = node.consequent[i];
+
+                    if (isLexicalDeclaration(statement)) {
+                        context.report({
+                            node: statement,
+                            messageId: "unexpected"
+                        });
+                    }
+                }
+            }
+        };
+
+    }
+};