noUnnecessaryQualifierRule.js 5.3KB

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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 utils = 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. /* tslint:enable:object-literal-sort-keys */
  29. Rule.FAILURE_STRING = function (name) {
  30. return "Qualifier is unnecessary since '" + name + "' is in scope.";
  31. };
  32. Rule.prototype.applyWithProgram = function (sourceFile, program) {
  33. return this.applyWithFunction(sourceFile, walk, undefined, program.getTypeChecker());
  34. };
  35. /* tslint:disable:object-literal-sort-keys */
  36. Rule.metadata = {
  37. ruleName: "no-unnecessary-qualifier",
  38. description: "Warns when a namespace qualifier (`A.x`) is unnecessary.",
  39. hasFix: true,
  40. optionsDescription: "Not configurable.",
  41. options: null,
  42. optionExamples: [true],
  43. type: "style",
  44. typescriptOnly: true,
  45. requiresTypeInfo: true,
  46. };
  47. return Rule;
  48. }(Lint.Rules.TypedRule));
  49. exports.Rule = Rule;
  50. function walk(ctx, checker) {
  51. var namespacesInScope = [];
  52. ts.forEachChild(ctx.sourceFile, cb);
  53. function cb(node) {
  54. switch (node.kind) {
  55. case ts.SyntaxKind.ModuleDeclaration:
  56. case ts.SyntaxKind.EnumDeclaration:
  57. namespacesInScope.push(node);
  58. ts.forEachChild(node, cb);
  59. namespacesInScope.pop();
  60. break;
  61. case ts.SyntaxKind.QualifiedName:
  62. var _a = node, left = _a.left, right = _a.right;
  63. visitNamespaceAccess(node, left, right);
  64. break;
  65. case ts.SyntaxKind.PropertyAccessExpression:
  66. var _b = node, expression = _b.expression, name = _b.name;
  67. if (utils.isEntityNameExpression(expression)) {
  68. visitNamespaceAccess(node, expression, name);
  69. break;
  70. }
  71. // falls through
  72. default:
  73. ts.forEachChild(node, cb);
  74. }
  75. }
  76. function visitNamespaceAccess(node, qualifier, name) {
  77. if (qualifierIsUnnecessary(qualifier, name)) {
  78. var fix = Lint.Replacement.deleteFromTo(qualifier.getStart(), name.getStart());
  79. ctx.addFailureAtNode(qualifier, Rule.FAILURE_STRING(qualifier.getText()), fix);
  80. }
  81. else {
  82. // Only look for nested qualifier errors if we didn't already fail on the outer qualifier.
  83. ts.forEachChild(node, cb);
  84. }
  85. }
  86. function qualifierIsUnnecessary(qualifier, name) {
  87. var namespaceSymbol = checker.getSymbolAtLocation(qualifier);
  88. if (namespaceSymbol === undefined || !symbolIsNamespaceInScope(namespaceSymbol)) {
  89. return false;
  90. }
  91. var accessedSymbol = checker.getSymbolAtLocation(name);
  92. if (accessedSymbol === undefined) {
  93. return false;
  94. }
  95. // If the symbol in scope is different, the qualifier is necessary.
  96. var fromScope = getSymbolInScope(qualifier, accessedSymbol.flags, name.text);
  97. return fromScope === undefined || symbolsAreEqual(accessedSymbol, fromScope);
  98. }
  99. function getSymbolInScope(node, flags, name) {
  100. // TODO:PERF `getSymbolsInScope` gets a long list. Is there a better way?
  101. var scope = checker.getSymbolsInScope(node, flags);
  102. return scope.find(function (scopeSymbol) { return scopeSymbol.name === name; });
  103. }
  104. function symbolIsNamespaceInScope(symbol) {
  105. var symbolDeclarations = symbol.getDeclarations();
  106. if (symbolDeclarations === undefined) {
  107. return false;
  108. }
  109. else if (symbolDeclarations.some(function (decl) { return namespacesInScope.some(function (ns) { return ns === decl; }); })) {
  110. return true;
  111. }
  112. var alias = tryGetAliasedSymbol(symbol, checker);
  113. return alias !== undefined && symbolIsNamespaceInScope(alias);
  114. }
  115. function symbolsAreEqual(accessed, inScope) {
  116. if (checker.getExportSymbolOfSymbol !== undefined) {
  117. inScope = checker.getExportSymbolOfSymbol(inScope);
  118. return accessed === inScope;
  119. }
  120. return accessed === inScope ||
  121. // For compatibility with typescript@2.5: compare declarations because the symbols don't have the same reference
  122. Lint.Utils.arraysAreEqual(accessed.declarations, inScope.declarations, function (a, b) { return a === b; });
  123. }
  124. }
  125. function tryGetAliasedSymbol(symbol, checker) {
  126. return utils.isSymbolFlagSet(symbol, ts.SymbolFlags.Alias) ? checker.getAliasedSymbol(symbol) : undefined;
  127. }