/** * @license * Copyright 2017 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. */ "use strict"; var __extends = (this && this.__extends) || (function () { var extendStatics = Object.setPrototypeOf || ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) || function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; }; return function (d, b) { extendStatics(d, b); function __() { this.constructor = d; } d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __()); }; })(); Object.defineProperty(exports, "__esModule", { value: true }); var ts = require("typescript"); var Lint = require("../index"); var Rule = (function (_super) { __extends(Rule, _super); function Rule() { return _super !== null && _super.apply(this, arguments) || this; } /* tslint:enable:object-literal-sort-keys */ Rule.FAILURE_STRING = function (negate) { return "This expression is unnecessarily compared to a boolean. Just " + (negate ? "negate it" : "use it directly") + "."; }; Rule.prototype.applyWithProgram = function (sourceFile, langSvc) { return this.applyWithWalker(new Walker(sourceFile, this.getOptions(), langSvc.getProgram())); }; return Rule; }(Lint.Rules.TypedRule)); /* tslint:disable:object-literal-sort-keys */ Rule.metadata = { ruleName: "no-boolean-literal-compare", description: "Warns on comparison to a boolean literal, as in `x === true`.", hasFix: true, optionsDescription: "Not configurable.", options: null, optionExamples: ["true"], type: "style", typescriptOnly: true, requiresTypeInfo: true, }; exports.Rule = Rule; var Walker = (function (_super) { __extends(Walker, _super); function Walker() { return _super !== null && _super.apply(this, arguments) || this; } Walker.prototype.visitBinaryExpression = function (node) { this.check(node); _super.prototype.visitBinaryExpression.call(this, node); }; Walker.prototype.check = function (node) { var comparison = deconstructComparison(node); if (comparison === undefined) { return; } var negate = comparison.negate, expression = comparison.expression; var type = this.getTypeChecker().getTypeAtLocation(expression); if (!Lint.isTypeFlagSet(type, ts.TypeFlags.Boolean)) { return; } var deleted = node.left === expression ? this.deleteFromTo(node.left.end, node.end) : this.deleteFromTo(node.getStart(), node.right.getStart()); var replacements = [deleted]; if (negate) { if (needsParenthesesForNegate(expression)) { replacements.push(this.appendText(node.getStart(), "!(")); replacements.push(this.appendText(node.getEnd(), ")")); } else { replacements.push(this.appendText(node.getStart(), "!")); } } this.addFailureAtNode(expression, Rule.FAILURE_STRING(negate), this.createFix.apply(this, replacements)); }; return Walker; }(Lint.ProgramAwareRuleWalker)); function needsParenthesesForNegate(node) { switch (node.kind) { case ts.SyntaxKind.AsExpression: case ts.SyntaxKind.BinaryExpression: return true; default: return false; } } function deconstructComparison(node) { var left = node.left, operatorToken = node.operatorToken, right = node.right; var eq = Lint.getEqualsKind(operatorToken); if (!eq) { return undefined; } var leftValue = booleanFromExpression(left); if (leftValue !== undefined) { return { negate: leftValue !== eq.isPositive, expression: right }; } var rightValue = booleanFromExpression(right); if (rightValue !== undefined) { return { negate: rightValue !== eq.isPositive, expression: left }; } return undefined; } function booleanFromExpression(node) { switch (node.kind) { case ts.SyntaxKind.TrueKeyword: return true; case ts.SyntaxKind.FalseKeyword: return false; default: return undefined; } }