--- /dev/null
+/**
+ * @fileoverview Rule to flag when return statement contains assignment
+ * @author Ilya Volodin
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("./utils/ast-utils");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+const SENTINEL_TYPE = /^(?:[a-zA-Z]+?Statement|ArrowFunctionExpression|FunctionExpression|ClassExpression)$/u;
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+ meta: {
+ type: "suggestion",
+
+ docs: {
+ description: "disallow assignment operators in `return` statements",
+ category: "Best Practices",
+ recommended: false,
+ url: "https://eslint.org/docs/rules/no-return-assign"
+ },
+
+ schema: [
+ {
+ enum: ["except-parens", "always"]
+ }
+ ],
+
+ messages: {
+ returnAssignment: "Return statement should not contain assignment.",
+ arrowAssignment: "Arrow function should not return assignment."
+ }
+ },
+
+ create(context) {
+ const always = (context.options[0] || "except-parens") !== "except-parens";
+ const sourceCode = context.getSourceCode();
+
+ return {
+ AssignmentExpression(node) {
+ if (!always && astUtils.isParenthesised(sourceCode, node)) {
+ return;
+ }
+
+ let currentChild = node;
+ let parent = currentChild.parent;
+
+ // Find ReturnStatement or ArrowFunctionExpression in ancestors.
+ while (parent && !SENTINEL_TYPE.test(parent.type)) {
+ currentChild = parent;
+ parent = parent.parent;
+ }
+
+ // Reports.
+ if (parent && parent.type === "ReturnStatement") {
+ context.report({
+ node: parent,
+ messageId: "returnAssignment"
+ });
+ } else if (parent && parent.type === "ArrowFunctionExpression" && parent.body === currentChild) {
+ context.report({
+ node: parent,
+ messageId: "arrowAssignment"
+ });
+ }
+ }
+ };
+ }
+};