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node_modules/eslint/lib/rules/no-useless-rename.js

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+/**
+ * @fileoverview Disallow renaming import, export, and destructured assignments to the same name.
+ * @author Kai Cataldo
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        type: "suggestion",
+
+        docs: {
+            description: "disallow renaming import, export, and destructured assignments to the same name",
+            category: "ECMAScript 6",
+            recommended: false,
+            url: "https://eslint.org/docs/rules/no-useless-rename"
+        },
+
+        fixable: "code",
+
+        schema: [
+            {
+                type: "object",
+                properties: {
+                    ignoreDestructuring: { type: "boolean", default: false },
+                    ignoreImport: { type: "boolean", default: false },
+                    ignoreExport: { type: "boolean", default: false }
+                },
+                additionalProperties: false
+            }
+        ]
+    },
+
+    create(context) {
+        const sourceCode = context.getSourceCode(),
+            options = context.options[0] || {},
+            ignoreDestructuring = options.ignoreDestructuring === true,
+            ignoreImport = options.ignoreImport === true,
+            ignoreExport = options.ignoreExport === true;
+
+        //--------------------------------------------------------------------------
+        // Helpers
+        //--------------------------------------------------------------------------
+
+        /**
+         * Reports error for unnecessarily renamed assignments
+         * @param {ASTNode} node node to report
+         * @param {ASTNode} initial node with initial name value
+         * @param {ASTNode} result node with new name value
+         * @param {string} type the type of the offending node
+         * @returns {void}
+         */
+        function reportError(node, initial, result, type) {
+            const name = initial.type === "Identifier" ? initial.name : initial.value;
+
+            return context.report({
+                node,
+                message: "{{type}} {{name}} unnecessarily renamed.",
+                data: {
+                    name,
+                    type
+                },
+                fix(fixer) {
+                    if (sourceCode.commentsExistBetween(initial, result)) {
+                        return null;
+                    }
+
+                    const replacementText = result.type === "AssignmentPattern"
+                        ? sourceCode.getText(result)
+                        : name;
+
+                    return fixer.replaceTextRange([
+                        initial.range[0],
+                        result.range[1]
+                    ], replacementText);
+                }
+            });
+        }
+
+        /**
+         * Checks whether a destructured assignment is unnecessarily renamed
+         * @param {ASTNode} node node to check
+         * @returns {void}
+         */
+        function checkDestructured(node) {
+            if (ignoreDestructuring) {
+                return;
+            }
+
+            for (const property of node.properties) {
+
+                /*
+                 * TODO: Remove after babel-eslint removes ExperimentalRestProperty
+                 * https://github.com/eslint/eslint/issues/12335
+                 */
+                if (property.type === "ExperimentalRestProperty") {
+                    continue;
+                }
+
+                /**
+                 * Properties using shorthand syntax and rest elements can not be renamed.
+                 * If the property is computed, we have no idea if a rename is useless or not.
+                 */
+                if (property.shorthand || property.type === "RestElement" || property.computed) {
+                    continue;
+                }
+
+                const key = (property.key.type === "Identifier" && property.key.name) || (property.key.type === "Literal" && property.key.value);
+                const renamedKey = property.value.type === "AssignmentPattern" ? property.value.left.name : property.value.name;
+
+                if (key === renamedKey) {
+                    reportError(property, property.key, property.value, "Destructuring assignment");
+                }
+            }
+        }
+
+        /**
+         * Checks whether an import is unnecessarily renamed
+         * @param {ASTNode} node node to check
+         * @returns {void}
+         */
+        function checkImport(node) {
+            if (ignoreImport) {
+                return;
+            }
+
+            if (node.imported.name === node.local.name &&
+                    node.imported.range[0] !== node.local.range[0]) {
+                reportError(node, node.imported, node.local, "Import");
+            }
+        }
+
+        /**
+         * Checks whether an export is unnecessarily renamed
+         * @param {ASTNode} node node to check
+         * @returns {void}
+         */
+        function checkExport(node) {
+            if (ignoreExport) {
+                return;
+            }
+
+            if (node.local.name === node.exported.name &&
+                    node.local.range[0] !== node.exported.range[0]) {
+                reportError(node, node.local, node.exported, "Export");
+            }
+
+        }
+
+        //--------------------------------------------------------------------------
+        // Public
+        //--------------------------------------------------------------------------
+
+        return {
+            ObjectPattern: checkDestructured,
+            ImportSpecifier: checkImport,
+            ExportSpecifier: checkExport
+        };
+    }
+};