noNonNullAssertionRule.js 3.6KB

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  1. "use strict";
  2. /**
  3. * @license
  4. * Copyright 2017 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 ts = require("typescript");
  21. var Lint = require("../index");
  22. var Rule = /** @class */ (function (_super) {
  23. tslib_1.__extends(Rule, _super);
  24. function Rule() {
  25. return _super !== null && _super.apply(this, arguments) || this;
  26. }
  27. Rule.prototype.apply = function (sourceFile) {
  28. return this.applyWithFunction(sourceFile, walk);
  29. };
  30. /* tslint:disable:object-literal-sort-keys */
  31. Rule.metadata = {
  32. ruleName: "no-non-null-assertion",
  33. description: "Disallows non-null assertions using the `!` postfix operator.",
  34. rationale: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Using non-null assertion cancels the benefits of the strict null checking mode.\n\n Instead of assuming objects exist:\n\n ```\n function foo(instance: MyClass | undefined) {\n instance!.doWork();\n }\n ```\n\n Either inform the strict type system that the object must exist:\n\n ```\n function foo(instance: MyClass) {\n instance.doWork();\n }\n ```\n\n Or verify that the instance exists, which will inform the type checker:\n\n ```\n function foo(instance: MyClass | undefined) {\n if (instance !== undefined) {\n instance.doWork();\n }\n }\n ```\n "], ["\n Using non-null assertion cancels the benefits of the strict null checking mode.\n\n Instead of assuming objects exist:\n\n \\`\\`\\`\n function foo(instance: MyClass | undefined) {\n instance!.doWork();\n }\n \\`\\`\\`\n\n Either inform the strict type system that the object must exist:\n\n \\`\\`\\`\n function foo(instance: MyClass) {\n instance.doWork();\n }\n \\`\\`\\`\n\n Or verify that the instance exists, which will inform the type checker:\n\n \\`\\`\\`\n function foo(instance: MyClass | undefined) {\n if (instance !== undefined) {\n instance.doWork();\n }\n }\n \\`\\`\\`\n "]))),
  35. optionsDescription: "Not configurable.",
  36. options: null,
  37. optionExamples: [true],
  38. type: "typescript",
  39. typescriptOnly: true,
  40. };
  41. /* tslint:enable:object-literal-sort-keys */
  42. Rule.FAILURE_STRING = "Forbidden non null assertion";
  43. return Rule;
  44. }(Lint.Rules.AbstractRule));
  45. exports.Rule = Rule;
  46. function walk(ctx) {
  47. return ts.forEachChild(ctx.sourceFile, function cb(node) {
  48. if (node.kind === ts.SyntaxKind.NonNullExpression) {
  49. ctx.addFailureAtNode(node, Rule.FAILURE_STRING);
  50. }
  51. return ts.forEachChild(node, cb);
  52. });
  53. }
  54. var templateObject_1;