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app_vue/node_modules/eslint/lib/rules/no-undef-init.js

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+/**
+ * @fileoverview Rule to flag when initializing to undefined
+ * @author Ilya Volodin
+ */
+
+"use strict";
+
+const astUtils = require("./utils/ast-utils");
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        type: "suggestion",
+
+        docs: {
+            description: "disallow initializing variables to `undefined`",
+            category: "Variables",
+            recommended: false,
+            url: "https://eslint.org/docs/rules/no-undef-init"
+        },
+
+        schema: [],
+        fixable: "code",
+
+        messages: {
+            unnecessaryUndefinedInit: "It's not necessary to initialize '{{name}}' to undefined."
+        }
+    },
+
+    create(context) {
+
+        const sourceCode = context.getSourceCode();
+
+        return {
+
+            VariableDeclarator(node) {
+                const name = sourceCode.getText(node.id),
+                    init = node.init && node.init.name,
+                    scope = context.getScope(),
+                    undefinedVar = astUtils.getVariableByName(scope, "undefined"),
+                    shadowed = undefinedVar && undefinedVar.defs.length > 0,
+                    lastToken = sourceCode.getLastToken(node);
+
+                if (init === "undefined" && node.parent.kind !== "const" && !shadowed) {
+                    context.report({
+                        node,
+                        messageId: "unnecessaryUndefinedInit",
+                        data: { name },
+                        fix(fixer) {
+                            if (node.parent.kind === "var") {
+                                return null;
+                            }
+
+                            if (node.id.type === "ArrayPattern" || node.id.type === "ObjectPattern") {
+
+                                // Don't fix destructuring assignment to `undefined`.
+                                return null;
+                            }
+
+                            if (sourceCode.commentsExistBetween(node.id, lastToken)) {
+                                return null;
+                            }
+
+                            return fixer.removeRange([node.id.range[1], node.range[1]]);
+                        }
+                    });
+                }
+            }
+        };
+
+    }
+};