noForInArrayRule.js 3.7KB

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  1. "use strict";
  2. /**
  3. * @license
  4. * Copyright 2016 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.applyWithProgram = function (sourceFile, program) {
  28. return this.applyWithFunction(sourceFile, walk, undefined, program.getTypeChecker());
  29. };
  30. /* tslint:disable:object-literal-sort-keys */
  31. Rule.metadata = {
  32. ruleName: "no-for-in-array",
  33. description: "Disallows iterating over an array with a for-in loop.",
  34. descriptionDetails: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n A for-in loop (`for (var k in o)`) iterates over the properties of an Object.\n\n While it is legal to use for-in loops with array types, it is not common.\n for-in will iterate over the indices of the array as strings, omitting any \"holes\" in\n the array.\n\n More common is to use for-of, which iterates over the values of an array.\n If you want to iterate over the indices, alternatives include:\n\n array.forEach((value, index) => { ... });\n for (const [index, value] of array.entries()) { ... }\n for (let i = 0; i < array.length; i++) { ... }\n "], ["\n A for-in loop (\\`for (var k in o)\\`) iterates over the properties of an Object.\n\n While it is legal to use for-in loops with array types, it is not common.\n for-in will iterate over the indices of the array as strings, omitting any \"holes\" in\n the array.\n\n More common is to use for-of, which iterates over the values of an array.\n If you want to iterate over the indices, alternatives include:\n\n array.forEach((value, index) => { ... });\n for (const [index, value] of array.entries()) { ... }\n for (let i = 0; i < array.length; i++) { ... }\n "]))),
  35. optionsDescription: "Not configurable.",
  36. options: null,
  37. optionExamples: [true],
  38. requiresTypeInfo: true,
  39. type: "functionality",
  40. typescriptOnly: false,
  41. };
  42. /* tslint:enable:object-literal-sort-keys */
  43. Rule.FAILURE_STRING = "for-in loops over arrays are forbidden. Use for-of or array.forEach instead.";
  44. return Rule;
  45. }(Lint.Rules.TypedRule));
  46. exports.Rule = Rule;
  47. function walk(ctx, checker) {
  48. return ts.forEachChild(ctx.sourceFile, function cb(node) {
  49. if (node.kind === ts.SyntaxKind.ForInStatement) {
  50. var type = checker.getTypeAtLocation(node.expression);
  51. if (type.symbol !== undefined && type.symbol.name === "Array" ||
  52. // tslint:disable-next-line:no-bitwise
  53. (type.flags & ts.TypeFlags.StringLike) !== 0) {
  54. ctx.addFailureAtNode(node, Rule.FAILURE_STRING);
  55. }
  56. }
  57. return ts.forEachChild(node, cb);
  58. });
  59. }
  60. var templateObject_1;