"use strict"; /** * @license * Copyright 2019 Palantir Technologies, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ Object.defineProperty(exports, "__esModule", { value: true }); var tslib_1 = require("tslib"); var tsutils = require("tsutils"); var ts = require("typescript"); var Lint = require("../index"); var TAUTOLOGY_DISCOVERED_ERROR_STRING = "Both sides of this equality comparison are the same, so the expression is either a tautology or a contradiction."; var Rule = /** @class */ (function (_super) { tslib_1.__extends(Rule, _super); function Rule() { return _super !== null && _super.apply(this, arguments) || this; } Rule.prototype.apply = function (sourceFile) { return this.applyWithFunction(sourceFile, walk); }; Rule.metadata = { description: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Enforces that relational/equality binary operators does not take two equal variables/literals as operands.\n Expression like 3 === 3, someVar === someVar, \"1\" > \"1\" are either a tautology or contradiction, and will produce an error.\n "], ["\n Enforces that relational/equality binary operators does not take two equal variables/literals as operands.\n Expression like 3 === 3, someVar === someVar, \"1\" > \"1\" are either a tautology or contradiction, and will produce an error.\n "]))), optionExamples: [true], options: null, optionsDescription: "Not configurable.", rationale: "Clean redundant code and unnecessary comparison of objects and literals.", ruleName: "no-tautology-expression", type: "functionality", typescriptOnly: false, }; return Rule; }(Lint.Rules.AbstractRule)); exports.Rule = Rule; function walk(context) { var cb = function (node) { if (tsutils.isBinaryExpression(node) && isRelationalOrLogicalOperator(node.operatorToken)) { if ((tsutils.isStringLiteral(node.left) && tsutils.isStringLiteral(node.right)) || (tsutils.isNumericLiteral(node.left) && tsutils.isNumericLiteral(node.right))) { if (node.left.text === node.right.text) { context.addFailureAtNode(node, TAUTOLOGY_DISCOVERED_ERROR_STRING); } } else if (tsutils.isIdentifier(node.left) && tsutils.isIdentifier(node.right)) { if (node.left.text === node.right.text) { context.addFailureAtNode(node, TAUTOLOGY_DISCOVERED_ERROR_STRING); } } else if (tsutils.isPropertyAccessExpression(node.left) && tsutils.isPropertyAccessExpression(node.right)) { if (node.left.expression.getText() === node.right.expression.getText()) { if (node.left.name.text === node.right.name.text) { context.addFailureAtNode(node, TAUTOLOGY_DISCOVERED_ERROR_STRING); } } } else if ((isBooleanLiteral(node.left) && isBooleanLiteral(node.right)) || (isNullLiteral(node.left) && isNullLiteral(node.right))) { context.addFailureAtNode(node, TAUTOLOGY_DISCOVERED_ERROR_STRING); } } return ts.forEachChild(node, cb); }; return ts.forEachChild(context.sourceFile, cb); } function isNullLiteral(node) { return node.kind === ts.SyntaxKind.NullKeyword; } function isBooleanLiteral(node) { return node.kind === ts.SyntaxKind.TrueKeyword || node.kind === ts.SyntaxKind.FalseKeyword; } function isRelationalOrLogicalOperator(operator) { return new Set([ ts.SyntaxKind.LessThanToken, ts.SyntaxKind.GreaterThanToken, ts.SyntaxKind.LessThanEqualsToken, ts.SyntaxKind.GreaterThanEqualsToken, ts.SyntaxKind.EqualsEqualsToken, ts.SyntaxKind.EqualsEqualsEqualsToken, ts.SyntaxKind.ExclamationEqualsToken, ts.SyntaxKind.ExclamationEqualsEqualsToken, ts.SyntaxKind.AmpersandAmpersandToken, ts.SyntaxKind.BarBarToken, ]).has(operator.kind); } var templateObject_1;