+++ /dev/null
-/**
- * @fileoverview Rule to disallow returning values from setters
- * @author Milos Djermanovic
- */
-
-"use strict";
-
-//------------------------------------------------------------------------------
-// Requirements
-//------------------------------------------------------------------------------
-
-const astUtils = require("./utils/ast-utils");
-const { findVariable } = require("eslint-utils");
-
-//------------------------------------------------------------------------------
-// Helpers
-//------------------------------------------------------------------------------
-
-/**
- * Determines whether the given identifier node is a reference to a global variable.
- * @param {ASTNode} node `Identifier` node to check.
- * @param {Scope} scope Scope to which the node belongs.
- * @returns {boolean} True if the identifier is a reference to a global variable.
- */
-function isGlobalReference(node, scope) {
- const variable = findVariable(scope, node);
-
- return variable !== null && variable.scope.type === "global" && variable.defs.length === 0;
-}
-
-/**
- * Determines whether the given node is an argument of the specified global method call, at the given `index` position.
- * E.g., for given `index === 1`, this function checks for `objectName.methodName(foo, node)`, where objectName is a global variable.
- * @param {ASTNode} node The node to check.
- * @param {Scope} scope Scope to which the node belongs.
- * @param {string} objectName Name of the global object.
- * @param {string} methodName Name of the method.
- * @param {number} index The given position.
- * @returns {boolean} `true` if the node is argument at the given position.
- */
-function isArgumentOfGlobalMethodCall(node, scope, objectName, methodName, index) {
- const parent = node.parent;
-
- return parent.type === "CallExpression" &&
- parent.arguments[index] === node &&
- parent.callee.type === "MemberExpression" &&
- astUtils.getStaticPropertyName(parent.callee) === methodName &&
- parent.callee.object.type === "Identifier" &&
- parent.callee.object.name === objectName &&
- isGlobalReference(parent.callee.object, scope);
-}
-
-/**
- * Determines whether the given node is used as a property descriptor.
- * @param {ASTNode} node The node to check.
- * @param {Scope} scope Scope to which the node belongs.
- * @returns {boolean} `true` if the node is a property descriptor.
- */
-function isPropertyDescriptor(node, scope) {
- if (
- isArgumentOfGlobalMethodCall(node, scope, "Object", "defineProperty", 2) ||
- isArgumentOfGlobalMethodCall(node, scope, "Reflect", "defineProperty", 2)
- ) {
- return true;
- }
-
- const parent = node.parent;
-
- if (
- parent.type === "Property" &&
- parent.value === node
- ) {
- const grandparent = parent.parent;
-
- if (
- grandparent.type === "ObjectExpression" &&
- (
- isArgumentOfGlobalMethodCall(grandparent, scope, "Object", "create", 1) ||
- isArgumentOfGlobalMethodCall(grandparent, scope, "Object", "defineProperties", 1)
- )
- ) {
- return true;
- }
- }
-
- return false;
-}
-
-/**
- * Determines whether the given function node is used as a setter function.
- * @param {ASTNode} node The node to check.
- * @param {Scope} scope Scope to which the node belongs.
- * @returns {boolean} `true` if the node is a setter.
- */
-function isSetter(node, scope) {
- const parent = node.parent;
-
- if (
- parent.kind === "set" &&
- parent.value === node
- ) {
-
- // Setter in an object literal or in a class
- return true;
- }
-
- if (
- parent.type === "Property" &&
- parent.value === node &&
- astUtils.getStaticPropertyName(parent) === "set" &&
- parent.parent.type === "ObjectExpression" &&
- isPropertyDescriptor(parent.parent, scope)
- ) {
-
- // Setter in a property descriptor
- return true;
- }
-
- return false;
-}
-
-/**
- * Finds function's outer scope.
- * @param {Scope} scope Function's own scope.
- * @returns {Scope} Function's outer scope.
- */
-function getOuterScope(scope) {
- const upper = scope.upper;
-
- if (upper.type === "function-expression-name") {
- return upper.upper;
- }
-
- return upper;
-}
-
-//------------------------------------------------------------------------------
-// Rule Definition
-//------------------------------------------------------------------------------
-
-module.exports = {
- meta: {
- type: "problem",
-
- docs: {
- description: "disallow returning values from setters",
- category: "Possible Errors",
- recommended: false,
- url: "https://eslint.org/docs/rules/no-setter-return"
- },
-
- schema: [],
-
- messages: {
- returnsValue: "Setter cannot return a value."
- }
- },
-
- create(context) {
- let funcInfo = null;
-
- /**
- * Creates and pushes to the stack a function info object for the given function node.
- * @param {ASTNode} node The function node.
- * @returns {void}
- */
- function enterFunction(node) {
- const outerScope = getOuterScope(context.getScope());
-
- funcInfo = {
- upper: funcInfo,
- isSetter: isSetter(node, outerScope)
- };
- }
-
- /**
- * Pops the current function info object from the stack.
- * @returns {void}
- */
- function exitFunction() {
- funcInfo = funcInfo.upper;
- }
-
- /**
- * Reports the given node.
- * @param {ASTNode} node Node to report.
- * @returns {void}
- */
- function report(node) {
- context.report({ node, messageId: "returnsValue" });
- }
-
- return {
-
- /*
- * Function declarations cannot be setters, but we still have to track them in the `funcInfo` stack to avoid
- * false positives, because a ReturnStatement node can belong to a function declaration inside a setter.
- *
- * Note: A previously declared function can be referenced and actually used as a setter in a property descriptor,
- * but that's out of scope for this rule.
- */
- FunctionDeclaration: enterFunction,
- FunctionExpression: enterFunction,
- ArrowFunctionExpression(node) {
- enterFunction(node);
-
- if (funcInfo.isSetter && node.expression) {
-
- // { set: foo => bar } property descriptor. Report implicit return 'bar' as the equivalent for a return statement.
- report(node.body);
- }
- },
-
- "FunctionDeclaration:exit": exitFunction,
- "FunctionExpression:exit": exitFunction,
- "ArrowFunctionExpression:exit": exitFunction,
-
- ReturnStatement(node) {
-
- // Global returns (e.g., at the top level of a Node module) don't have `funcInfo`.
- if (funcInfo && funcInfo.isSetter && node.argument) {
- report(node);
- }
- }
- };
- }
-};
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