noConditionalAssignmentRule.js 4.7KB

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  1. "use strict";
  2. /**
  3. * @license
  4. * Copyright 2015 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-conditional-assignment",
  34. description: "Disallows any type of assignment in conditionals.",
  35. descriptionDetails: "This applies to `do-while`, `for`, `if`, and `while` statements and conditional (ternary) expressions.",
  36. rationale: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Assignments in conditionals are often typos:\n for example `if (var1 = var2)` instead of `if (var1 == var2)`.\n They also can be an indicator of overly clever code which decreases maintainability."], ["\n Assignments in conditionals are often typos:\n for example \\`if (var1 = var2)\\` instead of \\`if (var1 == var2)\\`.\n They also can be an indicator of overly clever code which decreases maintainability."]))),
  37. optionsDescription: "Not configurable.",
  38. options: null,
  39. optionExamples: [true],
  40. type: "functionality",
  41. typescriptOnly: false,
  42. };
  43. /* tslint:enable:object-literal-sort-keys */
  44. Rule.FAILURE_STRING = "Assignments in conditional expressions are forbidden";
  45. return Rule;
  46. }(Lint.Rules.AbstractRule));
  47. exports.Rule = Rule;
  48. function walk(ctx) {
  49. var checking = 0;
  50. return ts.forEachChild(ctx.sourceFile, cb);
  51. function cb(node) {
  52. var kind = node.kind;
  53. if (!tsutils_1.isNodeKind(kind)) {
  54. return; // return early for tokens
  55. }
  56. switch (kind) {
  57. case ts.SyntaxKind.ConditionalExpression:
  58. check(node.condition);
  59. cb(node.whenTrue);
  60. cb(node.whenFalse);
  61. return;
  62. case ts.SyntaxKind.IfStatement:
  63. check(node.expression);
  64. cb(node.thenStatement);
  65. maybeCallback(cb, node.elseStatement);
  66. return;
  67. case ts.SyntaxKind.DoStatement:
  68. case ts.SyntaxKind.WhileStatement:
  69. check(node.expression);
  70. cb(node.statement);
  71. return;
  72. case ts.SyntaxKind.ForStatement:
  73. maybeCallback(cb, node.initializer);
  74. maybeCallback(check, node.condition);
  75. maybeCallback(cb, node.incrementor);
  76. cb(node.statement);
  77. return;
  78. }
  79. if (checking !== 0) {
  80. switch (kind) {
  81. case ts.SyntaxKind.BinaryExpression:
  82. if (tsutils_1.isAssignmentKind(node.operatorToken.kind)) {
  83. ctx.addFailureAtNode(node, Rule.FAILURE_STRING);
  84. }
  85. cb(node.left);
  86. cb(node.right);
  87. return;
  88. case ts.SyntaxKind.ParenthesizedExpression:
  89. case ts.SyntaxKind.NonNullExpression:
  90. case ts.SyntaxKind.AsExpression:
  91. case ts.SyntaxKind.TypeAssertionExpression:
  92. return cb(node.expression);
  93. case ts.SyntaxKind.PrefixUnaryExpression:
  94. return cb(node.operand);
  95. default:
  96. return noCheck(node);
  97. }
  98. }
  99. return ts.forEachChild(node, cb);
  100. }
  101. function check(node) {
  102. ++checking;
  103. cb(node);
  104. --checking;
  105. }
  106. function noCheck(node) {
  107. var old = checking;
  108. checking = 0;
  109. ts.forEachChild(node, cb);
  110. checking = old;
  111. }
  112. }
  113. function maybeCallback(cb, node) {
  114. if (node !== undefined) {
  115. cb(node);
  116. }
  117. }
  118. var templateObject_1;