"use strict"; var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) { if (k2 === undefined) k2 = k; var desc = Object.getOwnPropertyDescriptor(m, k); if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) { desc = { enumerable: true, get: function() { return m[k]; } }; } Object.defineProperty(o, k2, desc); }) : (function(o, m, k, k2) { if (k2 === undefined) k2 = k; o[k2] = m[k]; })); var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) { Object.defineProperty(o, "default", { enumerable: true, value: v }); }) : function(o, v) { o["default"] = v; }); var __importStar = (this && this.__importStar) || function (mod) { if (mod && mod.__esModule) return mod; var result = {}; if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k); __setModuleDefault(result, mod); return result; }; Object.defineProperty(exports, "__esModule", { value: true }); const utils_1 = require("@typescript-eslint/utils"); const tsutils = __importStar(require("ts-api-utils")); const ts = __importStar(require("typescript")); const util_1 = require("../util"); function parseChecksVoidReturn(checksVoidReturn) { switch (checksVoidReturn) { case false: return false; case true: case undefined: return { arguments: true, attributes: true, properties: true, returns: true, variables: true, }; default: return { arguments: checksVoidReturn.arguments ?? true, attributes: checksVoidReturn.attributes ?? true, properties: checksVoidReturn.properties ?? true, returns: checksVoidReturn.returns ?? true, variables: checksVoidReturn.variables ?? true, }; } } exports.default = (0, util_1.createRule)({ name: 'no-misused-promises', meta: { docs: { description: 'Disallow Promises in places not designed to handle them', recommended: 'recommended', requiresTypeChecking: true, }, messages: { voidReturnArgument: 'Promise returned in function argument where a void return was expected.', voidReturnVariable: 'Promise-returning function provided to variable where a void return was expected.', voidReturnProperty: 'Promise-returning function provided to property where a void return was expected.', voidReturnReturnValue: 'Promise-returning function provided to return value where a void return was expected.', voidReturnAttribute: 'Promise-returning function provided to attribute where a void return was expected.', conditional: 'Expected non-Promise value in a boolean conditional.', spread: 'Expected a non-Promise value to be spreaded in an object.', }, schema: [ { type: 'object', additionalProperties: false, properties: { checksConditionals: { type: 'boolean', }, checksVoidReturn: { oneOf: [ { type: 'boolean' }, { additionalProperties: false, properties: { arguments: { type: 'boolean' }, attributes: { type: 'boolean' }, properties: { type: 'boolean' }, returns: { type: 'boolean' }, variables: { type: 'boolean' }, }, type: 'object', }, ], }, checksSpreads: { type: 'boolean', }, }, }, ], type: 'problem', }, defaultOptions: [ { checksConditionals: true, checksVoidReturn: true, checksSpreads: true, }, ], create(context, [{ checksConditionals, checksVoidReturn, checksSpreads }]) { const services = (0, util_1.getParserServices)(context); const checker = services.program.getTypeChecker(); const checkedNodes = new Set(); const conditionalChecks = { ConditionalExpression: checkTestConditional, DoWhileStatement: checkTestConditional, ForStatement: checkTestConditional, IfStatement: checkTestConditional, LogicalExpression: checkConditional, 'UnaryExpression[operator="!"]'(node) { checkConditional(node.argument, true); }, WhileStatement: checkTestConditional, }; checksVoidReturn = parseChecksVoidReturn(checksVoidReturn); const voidReturnChecks = checksVoidReturn ? { ...(checksVoidReturn.arguments && { CallExpression: checkArguments, NewExpression: checkArguments, }), ...(checksVoidReturn.attributes && { JSXAttribute: checkJSXAttribute, }), ...(checksVoidReturn.properties && { Property: checkProperty, }), ...(checksVoidReturn.returns && { ReturnStatement: checkReturnStatement, }), ...(checksVoidReturn.variables && { AssignmentExpression: checkAssignment, VariableDeclarator: checkVariableDeclaration, }), } : {}; const spreadChecks = { SpreadElement: checkSpread, }; function checkTestConditional(node) { if (node.test) { checkConditional(node.test, true); } } /** * This function analyzes the type of a node and checks if it is a Promise in a boolean conditional. * It uses recursion when checking nested logical operators. * @param node The AST node to check. * @param isTestExpr Whether the node is a descendant of a test expression. */ function checkConditional(node, isTestExpr = false) { // prevent checking the same node multiple times if (checkedNodes.has(node)) { return; } checkedNodes.add(node); if (node.type === utils_1.AST_NODE_TYPES.LogicalExpression) { // ignore the left operand for nullish coalescing expressions not in a context of a test expression if (node.operator !== '??' || isTestExpr) { checkConditional(node.left, isTestExpr); } // we ignore the right operand when not in a context of a test expression if (isTestExpr) { checkConditional(node.right, isTestExpr); } return; } const tsNode = services.esTreeNodeToTSNodeMap.get(node); if (isAlwaysThenable(checker, tsNode)) { context.report({ messageId: 'conditional', node, }); } } function checkArguments(node) { const tsNode = services.esTreeNodeToTSNodeMap.get(node); const voidArgs = voidFunctionArguments(checker, tsNode); if (voidArgs.size === 0) { return; } for (const [index, argument] of node.arguments.entries()) { if (!voidArgs.has(index)) { continue; } const tsNode = services.esTreeNodeToTSNodeMap.get(argument); if (returnsThenable(checker, tsNode)) { context.report({ messageId: 'voidReturnArgument', node: argument, }); } } } function checkAssignment(node) { const tsNode = services.esTreeNodeToTSNodeMap.get(node); const varType = services.getTypeAtLocation(node.left); if (!isVoidReturningFunctionType(checker, tsNode.left, varType)) { return; } if (returnsThenable(checker, tsNode.right)) { context.report({ messageId: 'voidReturnVariable', node: node.right, }); } } function checkVariableDeclaration(node) { const tsNode = services.esTreeNodeToTSNodeMap.get(node); if (tsNode.initializer === undefined || node.init == null) { return; } const varType = services.getTypeAtLocation(node.id); if (!isVoidReturningFunctionType(checker, tsNode.initializer, varType)) { return; } if (returnsThenable(checker, tsNode.initializer)) { context.report({ messageId: 'voidReturnVariable', node: node.init, }); } } function checkProperty(node) { const tsNode = services.esTreeNodeToTSNodeMap.get(node); if (ts.isPropertyAssignment(tsNode)) { const contextualType = checker.getContextualType(tsNode.initializer); if (contextualType !== undefined && isVoidReturningFunctionType(checker, tsNode.initializer, contextualType) && returnsThenable(checker, tsNode.initializer)) { context.report({ messageId: 'voidReturnProperty', node: node.value, }); } } else if (ts.isShorthandPropertyAssignment(tsNode)) { const contextualType = checker.getContextualType(tsNode.name); if (contextualType !== undefined && isVoidReturningFunctionType(checker, tsNode.name, contextualType) && returnsThenable(checker, tsNode.name)) { context.report({ messageId: 'voidReturnProperty', node: node.value, }); } } else if (ts.isMethodDeclaration(tsNode)) { if (ts.isComputedPropertyName(tsNode.name)) { return; } const obj = tsNode.parent; // Below condition isn't satisfied unless something goes wrong, // but is needed for type checking. // 'node' does not include class method declaration so 'obj' is // always an object literal expression, but after converting 'node' // to TypeScript AST, its type includes MethodDeclaration which // does include the case of class method declaration. if (!ts.isObjectLiteralExpression(obj)) { return; } if (!returnsThenable(checker, tsNode)) { return; } const objType = checker.getContextualType(obj); if (objType === undefined) { return; } const propertySymbol = checker.getPropertyOfType(objType, tsNode.name.text); if (propertySymbol === undefined) { return; } const contextualType = checker.getTypeOfSymbolAtLocation(propertySymbol, tsNode.name); if (isVoidReturningFunctionType(checker, tsNode.name, contextualType)) { context.report({ messageId: 'voidReturnProperty', node: node.value, }); } return; } } function checkReturnStatement(node) { const tsNode = services.esTreeNodeToTSNodeMap.get(node); if (tsNode.expression === undefined || node.argument == null) { return; } const contextualType = checker.getContextualType(tsNode.expression); if (contextualType !== undefined && isVoidReturningFunctionType(checker, tsNode.expression, contextualType) && returnsThenable(checker, tsNode.expression)) { context.report({ messageId: 'voidReturnReturnValue', node: node.argument, }); } } function checkJSXAttribute(node) { if (node.value == null || node.value.type !== utils_1.AST_NODE_TYPES.JSXExpressionContainer) { return; } const expressionContainer = services.esTreeNodeToTSNodeMap.get(node.value); const expression = services.esTreeNodeToTSNodeMap.get(node.value.expression); const contextualType = checker.getContextualType(expressionContainer); if (contextualType !== undefined && isVoidReturningFunctionType(checker, expressionContainer, contextualType) && returnsThenable(checker, expression)) { context.report({ messageId: 'voidReturnAttribute', node: node.value, }); } } function checkSpread(node) { const tsNode = services.esTreeNodeToTSNodeMap.get(node); if (isSometimesThenable(checker, tsNode.expression)) { context.report({ messageId: 'spread', node: node.argument, }); } } return { ...(checksConditionals ? conditionalChecks : {}), ...(checksVoidReturn ? voidReturnChecks : {}), ...(checksSpreads ? spreadChecks : {}), }; }, }); function isSometimesThenable(checker, node) { const type = checker.getTypeAtLocation(node); for (const subType of tsutils.unionTypeParts(checker.getApparentType(type))) { if (tsutils.isThenableType(checker, node, subType)) { return true; } } return false; } // Variation on the thenable check which requires all forms of the type (read: // alternates in a union) to be thenable. Otherwise, you might be trying to // check if something is defined or undefined and get caught because one of the // branches is thenable. function isAlwaysThenable(checker, node) { const type = checker.getTypeAtLocation(node); for (const subType of tsutils.unionTypeParts(checker.getApparentType(type))) { const thenProp = subType.getProperty('then'); // If one of the alternates has no then property, it is not thenable in all // cases. if (thenProp === undefined) { return false; } // We walk through each variation of the then property. Since we know it // exists at this point, we just need at least one of the alternates to // be of the right form to consider it thenable. const thenType = checker.getTypeOfSymbolAtLocation(thenProp, node); let hasThenableSignature = false; for (const subType of tsutils.unionTypeParts(thenType)) { for (const signature of subType.getCallSignatures()) { if (signature.parameters.length !== 0 && isFunctionParam(checker, signature.parameters[0], node)) { hasThenableSignature = true; break; } } // We only need to find one variant of the then property that has a // function signature for it to be thenable. if (hasThenableSignature) { break; } } // If no flavors of the then property are thenable, we don't consider the // overall type to be thenable if (!hasThenableSignature) { return false; } } // If all variants are considered thenable (i.e. haven't returned false), we // consider the overall type thenable return true; } function isFunctionParam(checker, param, node) { const type = checker.getApparentType(checker.getTypeOfSymbolAtLocation(param, node)); for (const subType of tsutils.unionTypeParts(type)) { if (subType.getCallSignatures().length !== 0) { return true; } } return false; } function checkThenableOrVoidArgument(checker, node, type, index, thenableReturnIndices, voidReturnIndices) { if (isThenableReturningFunctionType(checker, node.expression, type)) { thenableReturnIndices.add(index); } else if (isVoidReturningFunctionType(checker, node.expression, type)) { // If a certain argument accepts both thenable and void returns, // a promise-returning function is valid if (!thenableReturnIndices.has(index)) { voidReturnIndices.add(index); } } } // Get the positions of arguments which are void functions (and not also // thenable functions). These are the candidates for the void-return check at // the current call site. // If the function parameters end with a 'rest' parameter, then we consider // the array type parameter (e.g. '...args:Array') when determining // if trailing arguments are candidates. function voidFunctionArguments(checker, node) { // 'new' can be used without any arguments, as in 'let b = new Object;' // In this case, there are no argument positions to check, so return early. if (!node.arguments) { return new Set(); } const thenableReturnIndices = new Set(); const voidReturnIndices = new Set(); const type = checker.getTypeAtLocation(node.expression); // We can't use checker.getResolvedSignature because it prefers an early '() => void' over a later '() => Promise' // See https://github.com/microsoft/TypeScript/issues/48077 for (const subType of tsutils.unionTypeParts(type)) { // Standard function calls and `new` have two different types of signatures const signatures = ts.isCallExpression(node) ? subType.getCallSignatures() : subType.getConstructSignatures(); for (const signature of signatures) { for (const [index, parameter] of signature.parameters.entries()) { const decl = parameter.valueDeclaration; let type = checker.getTypeOfSymbolAtLocation(parameter, node.expression); // If this is a array 'rest' parameter, check all of the argument indices // from the current argument to the end. // Note - we currently do not support 'spread' arguments - adding support for them // is tracked in https://github.com/typescript-eslint/typescript-eslint/issues/5744 if (decl && ts.isParameter(decl) && decl.dotDotDotToken) { if (checker.isArrayType(type)) { // Unwrap 'Array' to 'MaybeVoidFunction', // so that we'll handle it in the same way as a non-rest // 'param: MaybeVoidFunction' type = checker.getTypeArguments(type)[0]; for (let i = index; i < node.arguments.length; i++) { checkThenableOrVoidArgument(checker, node, type, i, thenableReturnIndices, voidReturnIndices); } } else if (checker.isTupleType(type)) { // Check each type in the tuple - for example, [boolean, () => void] would // add the index of the second tuple parameter to 'voidReturnIndices' const typeArgs = checker.getTypeArguments(type); for (let i = index; i < node.arguments.length && i - index < typeArgs.length; i++) { checkThenableOrVoidArgument(checker, node, typeArgs[i - index], i, thenableReturnIndices, voidReturnIndices); } } } else { checkThenableOrVoidArgument(checker, node, type, index, thenableReturnIndices, voidReturnIndices); } } } } for (const index of thenableReturnIndices) { voidReturnIndices.delete(index); } return voidReturnIndices; } /** * @returns Whether any call signature of the type has a thenable return type. */ function anySignatureIsThenableType(checker, node, type) { for (const signature of type.getCallSignatures()) { const returnType = signature.getReturnType(); if (tsutils.isThenableType(checker, node, returnType)) { return true; } } return false; } /** * @returns Whether type is a thenable-returning function. */ function isThenableReturningFunctionType(checker, node, type) { for (const subType of tsutils.unionTypeParts(type)) { if (anySignatureIsThenableType(checker, node, subType)) { return true; } } return false; } /** * @returns Whether type is a void-returning function. */ function isVoidReturningFunctionType(checker, node, type) { let hadVoidReturn = false; for (const subType of tsutils.unionTypeParts(type)) { for (const signature of subType.getCallSignatures()) { const returnType = signature.getReturnType(); // If a certain positional argument accepts both thenable and void returns, // a promise-returning function is valid if (tsutils.isThenableType(checker, node, returnType)) { return false; } hadVoidReturn ||= tsutils.isTypeFlagSet(returnType, ts.TypeFlags.Void); } } return hadVoidReturn; } /** * @returns Whether expression is a function that returns a thenable. */ function returnsThenable(checker, node) { const type = checker.getApparentType(checker.getTypeAtLocation(node)); if (anySignatureIsThenableType(checker, node, type)) { return true; } return false; } //# sourceMappingURL=no-misused-promises.js.map