4 * Copyright 2017 Palantir Technologies, Inc.
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
10 * http://www.apache.org/licenses/LICENSE-2.0
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
18 Object.defineProperty(exports, "__esModule", { value: true });
19 var tslib_1 = require("tslib");
20 var tsutils_1 = require("tsutils");
21 var ts = require("typescript");
22 var Lint = require("../index");
23 var Rule = /** @class */ (function (_super) {
24 tslib_1.__extends(Rule, _super);
26 return _super !== null && _super.apply(this, arguments) || this;
28 Rule.prototype.apply = function (sourceFile) {
29 return this.applyWithFunction(sourceFile, walk);
31 /* tslint:disable:object-literal-sort-keys max-line-length */
33 ruleName: "ban-comma-operator",
34 description: "Disallows the comma operator to be used.",
35 descriptionDetails: "[Read more about the comma operator here](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comma_Operator).",
36 rationale: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Using the comma operator can create a potential for many non-obvious bugs or lead to misunderstanding of code.\n\n ### Examples\n ```\n foo((bar, baz)); // evaluates to 'foo(baz)' because of the extra parens - confusing and not obvious\n ```\n\n ```\n switch (foo) {\n case 1, 2: // equals 'case 2' - probably intended 'case 1: case2:'\n return true;\n case 3:\n return false;\n }\n ```\n\n ```\n let x = (y = 1, z = 2); // x is equal to 2 - this may not be immediately obvious.\n ```\n "], ["\n Using the comma operator can create a potential for many non-obvious bugs or lead to misunderstanding of code.\n\n ### Examples\n \\`\\`\\`\n foo((bar, baz)); // evaluates to 'foo(baz)' because of the extra parens - confusing and not obvious\n \\`\\`\\`\n\n \\`\\`\\`\n switch (foo) {\n case 1, 2: // equals 'case 2' - probably intended 'case 1: case2:'\n return true;\n case 3:\n return false;\n }\n \\`\\`\\`\n\n \\`\\`\\`\n let x = (y = 1, z = 2); // x is equal to 2 - this may not be immediately obvious.\n \\`\\`\\`\n "]))),
38 optionsDescription: "",
39 optionExamples: [true],
40 type: "functionality",
41 typescriptOnly: false,
43 /* tslint:enable:object-literal-sort-keys max-line-length */
44 Rule.FAILURE_STRING = "Do not use comma operator here because it can be easily misunderstood or lead to unintended bugs.";
46 }(Lint.Rules.AbstractRule));
49 return ts.forEachChild(ctx.sourceFile, function cb(node) {
50 if (tsutils_1.isBinaryExpression(node) &&
51 node.operatorToken.kind === ts.SyntaxKind.CommaToken &&
52 !isForLoopIncrementor(node)) {
53 ctx.addFailureAtNode(node, Rule.FAILURE_STRING);
55 return ts.forEachChild(node, cb);
58 function isForLoopIncrementor(node) {
59 var parent = node.parent;
60 return (parent.kind === ts.SyntaxKind.ForStatement &&
61 parent.incrementor === node);