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

/**
 * @fileoverview Disallow renaming import, export, and destructured assignments to the same name.
 * @author Kai Cataldo
 */

"use strict";

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

const astUtils = require("./utils/ast-utils");

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
	meta: {
		type: "suggestion",

		defaultOptions: [
			{
				ignoreDestructuring: false,
				ignoreImport: false,
				ignoreExport: false,
			},
		],

		docs: {
			description:
				"Disallow renaming import, export, and destructured assignments to the same name",
			recommended: false,
			url: "https://eslint.org/docs/latest/rules/no-useless-rename",
		},

		fixable: "code",

		schema: [
			{
				type: "object",
				properties: {
					ignoreDestructuring: { type: "boolean" },
					ignoreImport: { type: "boolean" },
					ignoreExport: { type: "boolean" },
				},
				additionalProperties: false,
			},
		],

		messages: {
			unnecessarilyRenamed: "{{type}} {{name}} unnecessarily renamed.",
		},
	},

	create(context) {
		const sourceCode = context.sourceCode;
		const [{ ignoreDestructuring, ignoreImport, ignoreExport }] =
			context.options;

		//--------------------------------------------------------------------------
		// Helpers
		//--------------------------------------------------------------------------

		/**
		 * Reports error for unnecessarily renamed assignments
		 * @param {ASTNode} node node to report
		 * @param {ASTNode} initial node with initial name value
		 * @param {string} type the type of the offending node
		 * @returns {void}
		 */
		function reportError(node, initial, type) {
			const name =
				initial.type === "Identifier" ? initial.name : initial.value;

			return context.report({
				node,
				messageId: "unnecessarilyRenamed",
				data: {
					name,
					type,
				},
				fix(fixer) {
					const replacementNode =
						node.type === "Property" ? node.value : node.local;

					if (
						sourceCode.getCommentsInside(node).length >
						sourceCode.getCommentsInside(replacementNode).length
					) {
						return null;
					}

					// Don't autofix code such as `({foo: (foo) = a} = obj);`, parens are not allowed in shorthand properties.
					if (
						replacementNode.type === "AssignmentPattern" &&
						astUtils.isParenthesised(
							sourceCode,
							replacementNode.left,
						)
					) {
						return null;
					}

					return fixer.replaceText(
						node,
						sourceCode.getText(replacementNode),
					);
				},
			});
		}

		/**
		 * 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) {
				/**
				 * 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.type !== "Property" ||
					property.shorthand ||
					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,
						"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.range[0] !== node.local.range[0] &&
				astUtils.getModuleExportName(node.imported) === node.local.name
			) {
				reportError(node, node.imported, "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.range[0] !== node.exported.range[0] &&
				astUtils.getModuleExportName(node.local) ===
					astUtils.getModuleExportName(node.exported)
			) {
				reportError(node, node.local, "Export");
			}
		}

		//--------------------------------------------------------------------------
		// Public
		//--------------------------------------------------------------------------

		return {
			ObjectPattern: checkDestructured,
			ImportSpecifier: checkImport,
			ExportSpecifier: checkExport,
		};
	},
};