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 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 */
33 ruleName: "interface-over-type-literal",
34 description: "Prefer an interface declaration over a type literal (`type T = { ... }`)",
35 rationale: "Interfaces are generally preferred over type literals because interfaces can be implemented, extended and merged.",
36 optionsDescription: "Not configurable.",
38 optionExamples: [true],
43 /* tslint:enable:object-literal-sort-keys */
44 Rule.FAILURE_STRING = "Use an interface instead of a type literal.";
46 }(Lint.Rules.AbstractRule));
49 return ts.forEachChild(ctx.sourceFile, function cb(node) {
50 if (tsutils_1.isTypeAliasDeclaration(node) && tsutils_1.isTypeLiteralNode(node.type)) {
51 var typeKeyword = tsutils_1.getChildOfKind(node, ts.SyntaxKind.TypeKeyword, ctx.sourceFile);
53 // "type" -> "interface"
54 new Lint.Replacement(typeKeyword.end - 4, 4, "interface"),
55 // remove "=" and trivia up to the open curly brace of the type literal
56 Lint.Replacement.deleteFromTo(node.type.pos - 1, node.type.members.pos - 1),
58 // remove trailing semicolon if exists
59 if (ctx.sourceFile.text[node.end - 1] === ";") {
60 fix.push(Lint.Replacement.deleteText(node.end - 1, 1));
62 ctx.addFailureAtNode(node.name, Rule.FAILURE_STRING, fix);
64 return ts.forEachChild(node, cb);