noEmptyInterfaceRule.js 2.7KB

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  1. "use strict";
  2. /**
  3. * @license
  4. * Copyright 2013 Palantir Technologies, Inc.
  5. *
  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
  9. *
  10. * http://www.apache.org/licenses/LICENSE-2.0
  11. *
  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.
  17. */
  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);
  25. function Rule() {
  26. return _super !== null && _super.apply(this, arguments) || this;
  27. }
  28. Rule.prototype.apply = function (sourceFile) {
  29. return this.applyWithFunction(sourceFile, walk);
  30. };
  31. /* tslint:disable:object-literal-sort-keys */
  32. Rule.metadata = {
  33. ruleName: "no-empty-interface",
  34. description: "Forbids empty interfaces.",
  35. rationale: "An empty interface is equivalent to its supertype (or `{}`).",
  36. optionsDescription: "Not configurable.",
  37. options: null,
  38. type: "typescript",
  39. typescriptOnly: true,
  40. };
  41. /* tslint:enable:object-literal-sort-keys */
  42. Rule.FAILURE_STRING = "An empty interface is equivalent to `{}`.";
  43. Rule.FAILURE_STRING_FOR_EXTENDS = "An interface declaring no members is equivalent to its supertype.";
  44. return Rule;
  45. }(Lint.Rules.AbstractRule));
  46. exports.Rule = Rule;
  47. function walk(ctx) {
  48. return ts.forEachChild(ctx.sourceFile, function cb(node) {
  49. if (tsutils_1.isInterfaceDeclaration(node) &&
  50. node.members.length === 0 &&
  51. (node.heritageClauses === undefined || extendsOneTypeWithoutTypeArguments(node.heritageClauses[0]))) {
  52. return ctx.addFailureAtNode(node.name, node.heritageClauses !== undefined ? Rule.FAILURE_STRING_FOR_EXTENDS : Rule.FAILURE_STRING);
  53. }
  54. return ts.forEachChild(node, cb);
  55. });
  56. }
  57. function extendsOneTypeWithoutTypeArguments(_a) {
  58. var types = _a.types;
  59. switch (types.length) {
  60. case 0:
  61. return true; // don't crash on empty extends list
  62. case 1:
  63. return types[0].typeArguments === undefined; // allow interfaces that provide type arguments for the extended type
  64. default:
  65. return false; // allow interfaces extending more than one types
  66. }
  67. }