eslint-plugin-sonarjs
Version:
194 lines (193 loc) • 8.01 kB
JavaScript
;
/*
* SonarQube JavaScript Plugin
* Copyright (C) SonarSource Sàrl
* mailto:info AT sonarsource DOT com
*
* You can redistribute and/or modify this program under the terms of
* the Sonar Source-Available License Version 1, as published by SonarSource Sàrl.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the Sonar Source-Available License for more details.
*
* You should have received a copy of the Sonar Source-Available License
* along with this program; if not, see https://sonarsource.com/license/ssal/
*/
// https://sonarsource.github.io/rspec/#/rspec/S4335/javascript
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 () {
var ownKeys = function(o) {
ownKeys = Object.getOwnPropertyNames || function (o) {
var ar = [];
for (var k in o) if (Object.prototype.hasOwnProperty.call(o, k)) ar[ar.length] = k;
return ar;
};
return ownKeys(o);
};
return function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
if (mod != null) for (var k = ownKeys(mod), i = 0; i < k.length; i++) if (k[i] !== "default") __createBinding(result, mod, k[i]);
__setModuleDefault(result, mod);
return result;
};
})();
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.rule = void 0;
const typescript_1 = __importDefault(require("typescript"));
const generate_meta_js_1 = require("../helpers/generate-meta.js");
const ancestor_js_1 = require("../helpers/ancestor.js");
const parser_services_js_1 = require("../helpers/parser-services.js");
const meta = __importStar(require("./generated-meta.js"));
exports.rule = {
meta: (0, generate_meta_js_1.generateMeta)(meta, {
messages: {
removeIntersection: 'Remove this type without members or change this type intersection.',
simplifyIntersection: 'Simplify this intersection as it always has type "{{type}}".',
},
}),
create(context) {
const services = context.sourceCode.parserServices;
if (!(0, parser_services_js_1.isRequiredParserServices)(services)) {
return {};
}
function checkIntersectionType(node) {
const intersection = node;
const anyOrNever = intersection.types.find(typeNode => ['TSAnyKeyword', 'TSNeverKeyword'].includes(typeNode.type));
if (anyOrNever) {
context.report({
messageId: 'simplifyIntersection',
data: {
type: anyOrNever.type === 'TSAnyKeyword' ? 'any' : 'never',
},
node,
});
return;
}
checkTypesWithoutMembers(intersection, services);
}
function checkTypesWithoutMembers(intersection, parserServices) {
for (const typeNode of intersection.types) {
const tp = parserServices.program
.getTypeChecker()
.getTypeAtLocation(parserServices.esTreeNodeToTSNodeMap.get(typeNode));
if (!isTypeWithoutMembers(tp)) {
continue;
}
if (isLiteralUnionPattern(intersection)) {
continue;
}
if (isGenericTypePattern(intersection, typeNode, parserServices)) {
continue;
}
context.report({
messageId: 'removeIntersection',
node: typeNode,
});
}
}
return {
TSIntersectionType: checkIntersectionType,
};
},
};
function isTypeWithoutMembers(tp) {
return isNullLike(tp) || (isEmptyInterface(tp) && isStandaloneInterface(tp.symbol));
}
function isNullLike(tp) {
return (Boolean(tp.flags & typescript_1.default.TypeFlags.Null) ||
Boolean(tp.flags & typescript_1.default.TypeFlags.Undefined) ||
Boolean(tp.flags & typescript_1.default.TypeFlags.Void));
}
function isEmptyInterface(tp) {
return (tp.getProperties().length === 0 &&
(!tp.declaredIndexInfos ||
tp.declaredIndexInfos.length === 0));
}
function isStandaloneInterface(typeSymbol) {
// there is no declarations for `{}`
// otherwise check that none of declarations has a heritage clause (`extends X` or `implements X`)
if (!typeSymbol) {
return false;
}
const { declarations } = typeSymbol;
return (!declarations ||
declarations.every(declaration => {
return (isInterfaceDeclaration(declaration) && (declaration.heritageClauses ?? []).length === 0);
}));
}
function isInterfaceDeclaration(declaration) {
return declaration.kind === typescript_1.default.SyntaxKind.InterfaceDeclaration;
}
/**
* Detects the LiteralUnion pattern: `(X & {})` used within a union type to preserve
* IDE autocomplete for literal types while accepting any primitive value.
* Example: `'small' | 'medium' | 'large' | (string & {})`
*/
function isLiteralUnionPattern(intersection) {
if (intersection.types.length !== 2) {
return false;
}
const parent = (0, ancestor_js_1.getNodeParent)(intersection);
if (!parent || parent.type !== 'TSUnionType') {
return false;
}
const otherType = intersection.types.find(t => t.type !== 'TSTypeLiteral' || (t.members && t.members.length > 0));
if (!otherType) {
return false;
}
return (otherType.type === 'TSStringKeyword' ||
otherType.type === 'TSNumberKeyword' ||
otherType.type === 'TSTypeReference');
}
/**
* Detects generic type patterns where `& {}` serves a legitimate purpose:
* 1. Mapped type pattern: `{ [K in keyof T]: T[K] } & {}` - forces type flattening (Simplify/Prettify)
* 2. Generic type reference: `GenericType<T> & {}` where GenericType has type arguments
* 3. Type parameter reference: `T & {}` where T is a type parameter
*
* These patterns are used for type normalization and non-nullability constraints.
*/
function isGenericTypePattern(intersection, emptyTypeNode, parserServices) {
const siblingTypes = intersection.types.filter(t => t !== emptyTypeNode);
return siblingTypes.some(siblingType => {
// Pattern 1: Mapped type (Simplify/Prettify pattern)
if (siblingType.type === 'TSMappedType') {
return true;
}
// Pattern 2: Generic type reference with type arguments
if (siblingType.type === 'TSTypeReference' && siblingType.typeArguments) {
return true;
}
// Pattern 3: Type parameter reference (e.g., T & {})
if (siblingType.type === 'TSTypeReference') {
const tp = parserServices.program
.getTypeChecker()
.getTypeAtLocation(parserServices.esTreeNodeToTSNodeMap.get(siblingType));
if (tp.isTypeParameter()) {
return true;
}
}
return false;
});
}