"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 eslint_utils_1 = require("@typescript-eslint/utils/eslint-utils"); const tsutils = __importStar(require("ts-api-utils")); const ts = __importStar(require("typescript")); const util_1 = require("../util"); exports.default = (0, util_1.createRule)({ name: 'strict-boolean-expressions', meta: { type: 'suggestion', fixable: 'code', hasSuggestions: true, docs: { description: 'Disallow certain types in boolean expressions', requiresTypeChecking: true, }, schema: [ { type: 'object', properties: { allowString: { type: 'boolean' }, allowNumber: { type: 'boolean' }, allowNullableObject: { type: 'boolean' }, allowNullableBoolean: { type: 'boolean' }, allowNullableString: { type: 'boolean' }, allowNullableNumber: { type: 'boolean' }, allowNullableEnum: { 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.', conditionErrorNullableEnum: 'Unexpected nullable enum value in conditional. ' + 'Please handle the nullish/zero/NaN cases explicitly.', 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, allowNullableEnum: false, allowAny: false, allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing: false, }, ], create(context, [options]) { const services = (0, util_1.getParserServices)(context); const checker = services.program.getTypeChecker(); const compilerOptions = services.program.getCompilerOptions(); const sourceCode = (0, eslint_utils_1.getSourceCode)(context); 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 traversedNodes = new Set(); return { ConditionalExpression: traverseTestExpression, DoWhileStatement: traverseTestExpression, ForStatement: traverseTestExpression, IfStatement: traverseTestExpression, WhileStatement: traverseTestExpression, 'LogicalExpression[operator!="??"]': traverseLogicalExpression, 'UnaryExpression[operator="!"]': traverseUnaryLogicalExpression, }; /** * Inspects condition of a test expression. (`if`, `while`, `for`, etc.) */ function traverseTestExpression(node) { if (node.test == null) { return; } traverseNode(node.test, true); } /** * Inspects the argument of a unary logical expression (`!`). */ function traverseUnaryLogicalExpression(node) { traverseNode(node.argument, true); } /** * Inspects the arguments of a logical expression (`&&`, `||`). * * If the logical expression is a descendant of a test expression, * the `isCondition` flag should be set to true. * Otherwise, if the logical expression is there on it's own, * it's used for control flow and is not a condition itself. */ function traverseLogicalExpression(node, isCondition = false) { // left argument is always treated as a condition traverseNode(node.left, true); // if the logical expression is used for control flow, // then it's right argument is used for it's side effects only traverseNode(node.right, isCondition); } /** * Inspects any node. * * If it's a logical expression then it recursively traverses its arguments. * If it's any other kind of node then it's type is finally checked against the rule, * unless `isCondition` flag is set to false, in which case * it's assumed to be used for side effects only and is skipped. */ function traverseNode(node, isCondition) { // prevent checking the same node multiple times if (traversedNodes.has(node)) { return; } traversedNodes.add(node); // for logical operator, we check its operands if (node.type === utils_1.AST_NODE_TYPES.LogicalExpression && node.operator !== '??') { traverseLogicalExpression(node, isCondition); return; } // skip if node is not a condition if (!isCondition) { return; } checkNode(node); } /** * This function does the actual type check on a node. * It analyzes the type of a node and checks if it is allowed in a boolean context. */ function checkNode(node) { const type = (0, util_1.getConstrainedTypeAtLocation)(services, node); 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: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} ?? false`, }), }, { messageId: 'conditionFixCompareFalse', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} === false`, }), }, ], }); } else { // if (nullableBoolean) context.report({ node, messageId: 'conditionErrorNullableBoolean', suggest: [ { messageId: 'conditionFixDefaultFalse', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} ?? false`, }), }, { messageId: 'conditionFixCompareTrue', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${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: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code}.length === 0`, }), }, { messageId: 'conditionFixCompareEmptyString', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} === ""`, }), }, { messageId: 'conditionFixCastBoolean', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `!Boolean(${code})`, }), }, ], }); } else { // if (string) context.report({ node, messageId: 'conditionErrorString', suggest: [ { messageId: 'conditionFixCompareStringLength', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code}.length > 0`, }), }, { messageId: 'conditionFixCompareEmptyString', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} !== ""`, }), }, { messageId: 'conditionFixCastBoolean', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `Boolean(${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: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} == null`, }), }, { messageId: 'conditionFixDefaultEmptyString', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} ?? ""`, }), }, { messageId: 'conditionFixCastBoolean', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `!Boolean(${code})`, }), }, ], }); } else { // if (nullableString) context.report({ node, messageId: 'conditionErrorNullableString', suggest: [ { messageId: 'conditionFixCompareNullish', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} != null`, }), }, { messageId: 'conditionFixDefaultEmptyString', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} ?? ""`, }), }, { messageId: 'conditionFixCastBoolean', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `Boolean(${code})`, }), }, ], }); } } return; } // number if (is('number') || is('truthy number')) { if (!options.allowNumber) { if (isArrayLengthExpression(node, checker, services)) { if (isLogicalNegationExpression(node.parent)) { // if (!array.length) context.report({ node, messageId: 'conditionErrorNumber', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} === 0`, }), }); } else { // if (array.length) context.report({ node, messageId: 'conditionErrorNumber', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} > 0`, }), }); } } else if (isLogicalNegationExpression(node.parent)) { // if (!number) context.report({ node, messageId: 'conditionErrorNumber', suggest: [ { messageId: 'conditionFixCompareZero', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, // TODO: we have to compare to 0n if the type is bigint wrap: code => `${code} === 0`, }), }, { // TODO: don't suggest this for bigint because it can't be NaN messageId: 'conditionFixCompareNaN', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `Number.isNaN(${code})`, }), }, { messageId: 'conditionFixCastBoolean', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `!Boolean(${code})`, }), }, ], }); } else { // if (number) context.report({ node, messageId: 'conditionErrorNumber', suggest: [ { messageId: 'conditionFixCompareZero', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} !== 0`, }), }, { messageId: 'conditionFixCompareNaN', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `!Number.isNaN(${code})`, }), }, { messageId: 'conditionFixCastBoolean', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `Boolean(${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: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} == null`, }), }, { messageId: 'conditionFixDefaultZero', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} ?? 0`, }), }, { messageId: 'conditionFixCastBoolean', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `!Boolean(${code})`, }), }, ], }); } else { // if (nullableNumber) context.report({ node, messageId: 'conditionErrorNullableNumber', suggest: [ { messageId: 'conditionFixCompareNullish', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} != null`, }), }, { messageId: 'conditionFixDefaultZero', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} ?? 0`, }), }, { messageId: 'conditionFixCastBoolean', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `Boolean(${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', suggest: [ { messageId: 'conditionFixCompareNullish', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} == null`, }), }, ], }); } else { // if (nullableObject) context.report({ node, messageId: 'conditionErrorNullableObject', suggest: [ { messageId: 'conditionFixCompareNullish', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} != null`, }), }, ], }); } } return; } // nullable enum if (is('nullish', 'number', 'enum') || is('nullish', 'string', 'enum') || is('nullish', 'truthy number', 'enum') || is('nullish', 'truthy string', 'enum') || // mixed enums is('nullish', 'truthy number', 'truthy string', 'enum') || is('nullish', 'truthy number', 'string', 'enum') || is('nullish', 'truthy string', 'number', 'enum') || is('nullish', 'number', 'string', 'enum')) { if (!options.allowNullableEnum) { if (isLogicalNegationExpression(node.parent)) { context.report({ node, messageId: 'conditionErrorNullableEnum', fix: (0, util_1.getWrappingFixer)({ sourceCode, node: node.parent, innerNode: node, wrap: code => `${code} == null`, }), }); } else { context.report({ node, messageId: 'conditionErrorNullableEnum', fix: (0, util_1.getWrappingFixer)({ sourceCode, node, wrap: code => `${code} != null`, }), }); } } return; } // any if (is('any')) { if (!options.allowAny) { context.report({ node, messageId: 'conditionErrorAny', suggest: [ { messageId: 'conditionFixCastBoolean', fix: (0, util_1.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 ts-api-utils.unionTypeParts() if (booleans.length === 1) { tsutils.isTrueLiteralType(booleans[0]) ? 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.every(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.every(type => type.isNumberLiteral() && type.value !== 0)) { variantTypes.add('truthy number'); } else { variantTypes.add('number'); } } if (types.some(type => tsutils.isTypeFlagSet(type, ts.TypeFlags.EnumLike))) { variantTypes.add('enum'); } 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 => tsutils.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, services) { if (node.type !== utils_1.AST_NODE_TYPES.MemberExpression) { return false; } if (node.computed) { return false; } if (node.property.name !== 'length') { return false; } const objectType = (0, util_1.getConstrainedTypeAtLocation)(services, node.object); return (0, util_1.isTypeArrayTypeOrUnionOfArrayTypes)(objectType, typeChecker); } //# sourceMappingURL=strict-boolean-expressions.js.map