Initial commit (from f5274cbdce4ae7c9e4b937dcdf95ac70ae436d5f)

node_modules/tslint/lib/rules/noTautologyExpressionRule.js

@@ -0,0 +1,96 @@
+"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;