"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("tsutils")); const ts = __importStar(require("typescript")); const util = __importStar(require("../util")); exports.default = util.createRule({ name: 'strict-boolean-expressions', meta: { type: 'suggestion', fixable: 'code', hasSuggestions: true, docs: { description: 'Disallow certain types in boolean expressions', recommended: false, requiresTypeChecking: true, }, schema: [ { type: 'object', properties: { allowString: { type: 'boolean' }, allowNumber: { type: 'boolean' }, allowNullableObject: { type: 'boolean' }, allowNullableBoolean: { type: 'boolean' }, allowNullableString: { type: 'boolean' }, allowNullableNumber: { type: 'boolean' }, allowAny: { type: 'boolean' }, allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing: { type: 'boolean', }, }, additionalProperties: false, }, ], messages: { conditionErrorOther: 'Unexpected value in conditional. ' + 'A boolean expression is required.', conditionErrorAny: 'Unexpected any value in conditional. ' + 'An explicit comparison or type cast is required.', conditionErrorNullish: 'Unexpected nullish value in conditional. ' + 'The condition is always false.', conditionErrorNullableBoolean: 'Unexpected nullable boolean value in conditional. ' + 'Please handle the nullish case explicitly.', conditionErrorString: 'Unexpected string value in conditional. ' + 'An explicit empty string check is required.', conditionErrorNullableString: 'Unexpected nullable string value in conditional. ' + 'Please handle the nullish/empty cases explicitly.', conditionErrorNumber: 'Unexpected number value in conditional. ' + 'An explicit zero/NaN check is required.', conditionErrorNullableNumber: 'Unexpected nullable number value in conditional. ' + 'Please handle the nullish/zero/NaN cases explicitly.', conditionErrorObject: 'Unexpected object value in conditional. ' + 'The condition is always true.', conditionErrorNullableObject: 'Unexpected nullable object value in conditional. ' + 'An explicit null check is required.', noStrictNullCheck: 'This rule requires the `strictNullChecks` compiler option to be turned on to function correctly.', conditionFixDefaultFalse: 'Explicitly treat nullish value the same as false (`value ?? false`)', conditionFixDefaultEmptyString: 'Explicitly treat nullish value the same as an empty string (`value ?? ""`)', conditionFixDefaultZero: 'Explicitly treat nullish value the same as 0 (`value ?? 0`)', conditionFixCompareNullish: 'Change condition to check for null/undefined (`value != null`)', conditionFixCastBoolean: 'Explicitly cast value to a boolean (`Boolean(value)`)', conditionFixCompareTrue: 'Change condition to check if true (`value === true`)', conditionFixCompareFalse: 'Change condition to check if false (`value === false`)', conditionFixCompareStringLength: "Change condition to check string's length (`value.length !== 0`)", conditionFixCompareEmptyString: 'Change condition to check for empty string (`value !== ""`)', conditionFixCompareZero: 'Change condition to check for 0 (`value !== 0`)', conditionFixCompareNaN: 'Change condition to check for NaN (`!Number.isNaN(value)`)', }, }, defaultOptions: [ { allowString: true, allowNumber: true, allowNullableObject: true, allowNullableBoolean: false, allowNullableString: false, allowNullableNumber: false, allowAny: false, allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing: false, }, ], create(context, [options]) { const parserServices = util.getParserServices(context); const typeChecker = parserServices.program.getTypeChecker(); const compilerOptions = parserServices.program.getCompilerOptions(); const sourceCode = context.getSourceCode(); const isStrictNullChecks = tsutils.isStrictCompilerOptionEnabled(compilerOptions, 'strictNullChecks'); if (!isStrictNullChecks && options.allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing !== true) { context.report({ loc: { start: { line: 0, column: 0 }, end: { line: 0, column: 0 }, }, messageId: 'noStrictNullCheck', }); } const checkedNodes = new Set(); return { ConditionalExpression: checkTestExpression, DoWhileStatement: checkTestExpression, ForStatement: checkTestExpression, IfStatement: checkTestExpression, WhileStatement: checkTestExpression, 'LogicalExpression[operator!="??"]': checkNode, 'UnaryExpression[operator="!"]': checkUnaryLogicalExpression, }; function checkTestExpression(node) { if (node.test == null) { return; } checkNode(node.test, true); } function checkUnaryLogicalExpression(node) { checkNode(node.argument, true); } /** * This function analyzes the type of a node and checks if it is allowed in a boolean context. * It can recurse when checking nested logical operators, so that only the outermost operands are reported. * The right operand of a logical expression is ignored unless it's a part of a test expression (if/while/ternary/etc). * @param node The AST node to check. * @param isTestExpr Whether the node is a descendant of a test expression. */ function checkNode(node, isTestExpr = false) { // prevent checking the same node multiple times if (checkedNodes.has(node)) { return; } checkedNodes.add(node); // for logical operator, we check its operands if (node.type === utils_1.AST_NODE_TYPES.LogicalExpression && node.operator !== '??') { checkNode(node.left, isTestExpr); // we ignore the right operand when not in a context of a test expression if (isTestExpr) { checkNode(node.right, isTestExpr); } return; } const tsNode = parserServices.esTreeNodeToTSNodeMap.get(node); const type = util.getConstrainedTypeAtLocation(typeChecker, tsNode); const types = inspectVariantTypes(tsutils.unionTypeParts(type)); const is = (...wantedTypes) => types.size === wantedTypes.length && wantedTypes.every(type => types.has(type)); // boolean if (is('boolean') || is('truthy boolean')) { // boolean is always okay return; } // never if (is('never')) { // never is always okay return; } // nullish if (is('nullish')) { // condition is always false context.report({ node, messageId: 'conditionErrorNullish' }); return; } // Known edge case: boolean `true` and nullish values are always valid boolean expressions if (is('nullish', 'truthy boolean')) { return; } // nullable boolean if (is('nullish', 'boolean')) { if (!options.allowNullableBoolean) { if (isLogicalNegationExpression(node.parent)) { // if (!nullableBoolean) context.report({ node, messageId: 'conditionErrorNullableBoolean', suggest: [ { messageId: 'conditionFixDefaultFalse', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} ?? false`, }), }, { messageId: 'conditionFixCompareFalse', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} === false`, }), }, ], }); } else { // if (nullableBoolean) context.report({ node, messageId: 'conditionErrorNullableBoolean', suggest: [ { messageId: 'conditionFixDefaultFalse', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} ?? false`, }), }, { messageId: 'conditionFixCompareTrue', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} === true`, }), }, ], }); } } return; } // Known edge case: truthy primitives and nullish values are always valid boolean expressions if ((options.allowNumber && is('nullish', 'truthy number')) || (options.allowString && is('nullish', 'truthy string'))) { return; } // string if (is('string') || is('truthy string')) { if (!options.allowString) { if (isLogicalNegationExpression(node.parent)) { // if (!string) context.report({ node, messageId: 'conditionErrorString', suggest: [ { messageId: 'conditionFixCompareStringLength', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code}.length === 0`, }), }, { messageId: 'conditionFixCompareEmptyString', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} === ""`, }), }, { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `!Boolean(${code})`, }), }, ], }); } else { // if (string) context.report({ node, messageId: 'conditionErrorString', suggest: [ { messageId: 'conditionFixCompareStringLength', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code}.length > 0`, }), }, { messageId: 'conditionFixCompareEmptyString', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} !== ""`, }), }, { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `Boolean(${code})`, }), }, ], }); } } return; } // nullable string if (is('nullish', 'string')) { if (!options.allowNullableString) { if (isLogicalNegationExpression(node.parent)) { // if (!nullableString) context.report({ node, messageId: 'conditionErrorNullableString', suggest: [ { messageId: 'conditionFixCompareNullish', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} == null`, }), }, { messageId: 'conditionFixDefaultEmptyString', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} ?? ""`, }), }, { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `!Boolean(${code})`, }), }, ], }); } else { // if (nullableString) context.report({ node, messageId: 'conditionErrorNullableString', suggest: [ { messageId: 'conditionFixCompareNullish', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} != null`, }), }, { messageId: 'conditionFixDefaultEmptyString', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} ?? ""`, }), }, { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `Boolean(${code})`, }), }, ], }); } } return; } // number if (is('number') || is('truthy number')) { if (!options.allowNumber) { if (isArrayLengthExpression(node, typeChecker, parserServices)) { if (isLogicalNegationExpression(node.parent)) { // if (!array.length) context.report({ node, messageId: 'conditionErrorNumber', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} === 0`, }), }); } else { // if (array.length) context.report({ node, messageId: 'conditionErrorNumber', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} > 0`, }), }); } } else if (isLogicalNegationExpression(node.parent)) { // if (!number) context.report({ node, messageId: 'conditionErrorNumber', suggest: [ { messageId: 'conditionFixCompareZero', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, // TODO: we have to compare to 0n if the type is bigint wrap: code => `${code} === 0`, }), }, { // TODO: don't suggest this for bigint because it can't be NaN messageId: 'conditionFixCompareNaN', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `Number.isNaN(${code})`, }), }, { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `!Boolean(${code})`, }), }, ], }); } else { // if (number) context.report({ node, messageId: 'conditionErrorNumber', suggest: [ { messageId: 'conditionFixCompareZero', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} !== 0`, }), }, { messageId: 'conditionFixCompareNaN', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `!Number.isNaN(${code})`, }), }, { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `Boolean(${code})`, }), }, ], }); } } return; } // nullable number if (is('nullish', 'number')) { if (!options.allowNullableNumber) { if (isLogicalNegationExpression(node.parent)) { // if (!nullableNumber) context.report({ node, messageId: 'conditionErrorNullableNumber', suggest: [ { messageId: 'conditionFixCompareNullish', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} == null`, }), }, { messageId: 'conditionFixDefaultZero', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} ?? 0`, }), }, { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `!Boolean(${code})`, }), }, ], }); } else { // if (nullableNumber) context.report({ node, messageId: 'conditionErrorNullableNumber', suggest: [ { messageId: 'conditionFixCompareNullish', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} != null`, }), }, { messageId: 'conditionFixDefaultZero', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} ?? 0`, }), }, { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `Boolean(${code})`, }), }, ], }); } } return; } // object if (is('object')) { // condition is always true context.report({ node, messageId: 'conditionErrorObject' }); return; } // nullable object if (is('nullish', 'object')) { if (!options.allowNullableObject) { if (isLogicalNegationExpression(node.parent)) { // if (!nullableObject) context.report({ node, messageId: 'conditionErrorNullableObject', fix: util.getWrappingFixer({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} == null`, }), }); } else { // if (nullableObject) context.report({ node, messageId: 'conditionErrorNullableObject', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `${code} != null`, }), }); } } return; } // any if (is('any')) { if (!options.allowAny) { context.report({ node, messageId: 'conditionErrorAny', suggest: [ { messageId: 'conditionFixCastBoolean', fix: util.getWrappingFixer({ sourceCode, node, wrap: code => `Boolean(${code})`, }), }, ], }); } return; } // other context.report({ node, messageId: 'conditionErrorOther' }); } /** * Check union variants for the types we care about */ function inspectVariantTypes(types) { const variantTypes = new Set(); if (types.some(type => tsutils.isTypeFlagSet(type, ts.TypeFlags.Null | ts.TypeFlags.Undefined | ts.TypeFlags.VoidLike))) { variantTypes.add('nullish'); } const booleans = types.filter(type => tsutils.isTypeFlagSet(type, ts.TypeFlags.BooleanLike)); // If incoming type is either "true" or "false", there will be one type // object with intrinsicName set accordingly // If incoming type is boolean, there will be two type objects with // intrinsicName set "true" and "false" each because of tsutils.unionTypeParts() if (booleans.length === 1) { tsutils.isBooleanLiteralType(booleans[0], true) ? variantTypes.add('truthy boolean') : variantTypes.add('boolean'); } else if (booleans.length === 2) { variantTypes.add('boolean'); } const strings = types.filter(type => tsutils.isTypeFlagSet(type, ts.TypeFlags.StringLike)); if (strings.length) { if (strings.some(type => type.isStringLiteral() && type.value !== '')) { variantTypes.add('truthy string'); } else { variantTypes.add('string'); } } const numbers = types.filter(type => tsutils.isTypeFlagSet(type, ts.TypeFlags.NumberLike | ts.TypeFlags.BigIntLike)); if (numbers.length) { if (numbers.some(type => type.isNumberLiteral() && type.value !== 0)) { variantTypes.add('truthy number'); } else { variantTypes.add('number'); } } if (types.some(type => !tsutils.isTypeFlagSet(type, ts.TypeFlags.Null | ts.TypeFlags.Undefined | ts.TypeFlags.VoidLike | ts.TypeFlags.BooleanLike | ts.TypeFlags.StringLike | ts.TypeFlags.NumberLike | ts.TypeFlags.BigIntLike | ts.TypeFlags.TypeParameter | ts.TypeFlags.Any | ts.TypeFlags.Unknown | ts.TypeFlags.Never))) { variantTypes.add('object'); } if (types.some(type => util.isTypeFlagSet(type, ts.TypeFlags.TypeParameter | ts.TypeFlags.Any | ts.TypeFlags.Unknown))) { variantTypes.add('any'); } if (types.some(type => tsutils.isTypeFlagSet(type, ts.TypeFlags.Never))) { variantTypes.add('never'); } return variantTypes; } }, }); function isLogicalNegationExpression(node) { return node.type === utils_1.AST_NODE_TYPES.UnaryExpression && node.operator === '!'; } function isArrayLengthExpression(node, typeChecker, parserServices) { if (node.type !== utils_1.AST_NODE_TYPES.MemberExpression) { return false; } if (node.computed) { return false; } if (node.property.name !== 'length') { return false; } const objectTsNode = parserServices.esTreeNodeToTSNodeMap.get(node.object); const objectType = util.getConstrainedTypeAtLocation(typeChecker, objectTsNode); return util.isTypeArrayTypeOrUnionOfArrayTypes(objectType, typeChecker); } //# sourceMappingURL=strict-boolean-expressions.js.map