4 * Copyright 2013 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 noEmptyInterface_examples_1 = require("./code-examples/noEmptyInterface.examples");
24 var Rule = /** @class */ (function (_super) {
25 tslib_1.__extends(Rule, _super);
27 return _super !== null && _super.apply(this, arguments) || this;
29 Rule.prototype.apply = function (sourceFile) {
30 return this.applyWithFunction(sourceFile, walk);
32 /* tslint:disable:object-literal-sort-keys */
34 ruleName: "no-empty-interface",
35 description: "Forbids empty interfaces.",
36 rationale: "An empty interface is equivalent to its supertype (or `{}`).",
37 optionsDescription: "Not configurable.",
41 codeExamples: noEmptyInterface_examples_1.codeExamples,
43 /* tslint:enable:object-literal-sort-keys */
44 Rule.FAILURE_STRING = "An empty interface is equivalent to `{}`.";
45 Rule.FAILURE_STRING_FOR_EXTENDS = "An interface declaring no members is equivalent to its supertype.";
47 }(Lint.Rules.AbstractRule));
50 return ts.forEachChild(ctx.sourceFile, function cb(node) {
51 if (tsutils_1.isInterfaceDeclaration(node) &&
52 node.members.length === 0 &&
53 (node.heritageClauses === undefined ||
54 extendsOneTypeWithoutTypeArguments(node.heritageClauses[0]))) {
55 return ctx.addFailureAtNode(node.name, node.heritageClauses !== undefined
56 ? Rule.FAILURE_STRING_FOR_EXTENDS
57 : Rule.FAILURE_STRING);
59 return ts.forEachChild(node, cb);
62 function extendsOneTypeWithoutTypeArguments(_a) {
64 switch (types.length) {
66 return true; // don't crash on empty extends list
68 return types[0].typeArguments === undefined; // allow interfaces that provide type arguments for the extended type
70 return false; // allow interfaces extending more than one types