node_modules/eslint/lib/rules/prefer-object-has-own.js

/**
 * @fileoverview Prefers Object.hasOwn() instead of Object.prototype.hasOwnProperty.call()
 * @author Nitin Kumar
 * @author Gautam Arora
 */

"use strict";

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

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

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

/**
 * Checks if the given node is considered to be an access to a property of `Object.prototype`.
 * @param {ASTNode} node `MemberExpression` node to evaluate.
 * @returns {boolean} `true` if `node.object` is `Object`, `Object.prototype`, or `{}` (empty 'ObjectExpression' node).
 */
function hasLeftHandObject(node) {
	/*
	 * ({}).hasOwnProperty.call(obj, prop) - `true`
	 * ({ foo }.hasOwnProperty.call(obj, prop)) - `false`, object literal should be empty
	 */
	if (
		node.object.type === "ObjectExpression" &&
		node.object.properties.length === 0
	) {
		return true;
	}

	const objectNodeToCheck =
		node.object.type === "MemberExpression" &&
		astUtils.getStaticPropertyName(node.object) === "prototype"
			? node.object.object
			: node.object;

	if (
		objectNodeToCheck.type === "Identifier" &&
		objectNodeToCheck.name === "Object"
	) {
		return true;
	}

	return false;
}

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

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
	meta: {
		type: "suggestion",
		docs: {
			description:
				"Disallow use of `Object.prototype.hasOwnProperty.call()` and prefer use of `Object.hasOwn()`",
			recommended: false,
			url: "https://eslint.org/docs/latest/rules/prefer-object-has-own",
		},
		schema: [],
		messages: {
			useHasOwn:
				"Use 'Object.hasOwn()' instead of 'Object.prototype.hasOwnProperty.call()'.",
		},
		fixable: "code",
	},
	create(context) {
		const sourceCode = context.sourceCode;

		return {
			CallExpression(node) {
				if (
					!(
						node.callee.type === "MemberExpression" &&
						node.callee.object.type === "MemberExpression"
					)
				) {
					return;
				}

				const calleePropertyName = astUtils.getStaticPropertyName(
					node.callee,
				);
				const objectPropertyName = astUtils.getStaticPropertyName(
					node.callee.object,
				);
				const isObject = hasLeftHandObject(node.callee.object);

				// check `Object` scope
				const scope = sourceCode.getScope(node);
				const variable = astUtils.getVariableByName(scope, "Object");

				if (
					calleePropertyName === "call" &&
					objectPropertyName === "hasOwnProperty" &&
					isObject &&
					variable &&
					variable.scope.type === "global"
				) {
					context.report({
						node,
						messageId: "useHasOwn",
						fix(fixer) {
							if (
								sourceCode.getCommentsInside(node.callee)
									.length > 0
							) {
								return null;
							}

							const tokenJustBeforeNode =
								sourceCode.getTokenBefore(node.callee, {
									includeComments: true,
								});

							// for https://github.com/eslint/eslint/pull/15346#issuecomment-991417335
							if (
								tokenJustBeforeNode &&
								tokenJustBeforeNode.range[1] ===
									node.callee.range[0] &&
								!astUtils.canTokensBeAdjacent(
									tokenJustBeforeNode,
									"Object.hasOwn",
								)
							) {
								return fixer.replaceText(
									node.callee,
									" Object.hasOwn",
								);
							}

							return fixer.replaceText(
								node.callee,
								"Object.hasOwn",
							);
						},
					});
				}
			},
		};
	},
};