useIsnanRule.js 3.2KB

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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: "use-isnan",
  34. description: "Enforces use of the `isNaN()` function to check for NaN references instead of a comparison to the `NaN` constant.",
  35. rationale: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Since `NaN !== NaN`, comparisons with regular operators will produce unexpected results.\n So, instead of `if (myVar === NaN)`, do `if (isNaN(myVar))`."], ["\n Since \\`NaN !== NaN\\`, comparisons with regular operators will produce unexpected results.\n So, instead of \\`if (myVar === NaN)\\`, do \\`if (isNaN(myVar))\\`."]))),
  36. optionsDescription: "Not configurable.",
  37. options: null,
  38. optionExamples: [true],
  39. type: "functionality",
  40. typescriptOnly: false,
  41. };
  42. /* tslint:enable:object-literal-sort-keys */
  43. Rule.FAILURE_STRING = "Found an invalid comparison for NaN: ";
  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.isBinaryExpression(node)) {
  50. switch (node.operatorToken.kind) {
  51. case ts.SyntaxKind.LessThanToken:
  52. case ts.SyntaxKind.GreaterThanToken:
  53. case ts.SyntaxKind.LessThanEqualsToken:
  54. case ts.SyntaxKind.GreaterThanEqualsToken:
  55. case ts.SyntaxKind.EqualsEqualsToken:
  56. case ts.SyntaxKind.ExclamationEqualsToken:
  57. case ts.SyntaxKind.EqualsEqualsEqualsToken:
  58. case ts.SyntaxKind.ExclamationEqualsEqualsToken:
  59. if (isExpressionNaN(node.right) || isExpressionNaN(node.left)) {
  60. ctx.addFailureAtNode(node, Rule.FAILURE_STRING + node.getText(ctx.sourceFile));
  61. }
  62. }
  63. }
  64. return ts.forEachChild(node, cb);
  65. });
  66. }
  67. function isExpressionNaN(node) {
  68. return node.kind === ts.SyntaxKind.Identifier && node.text === "NaN";
  69. }
  70. var templateObject_1;